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Reviews > Water Treatment > Ultraviolet > SteriPEN Adventurer Opti > Test Report by Gail Staisil

 SteriPEN Adventurer Opti
Test Series by: Gail Staisil, Marquette, Michigan

Page Contents:

Initial Report:
April 26, 2010Author

Tester Information
Gail Staisil
Age: 57
Gender: Female
Height: 5' 9" (1.75 m)
Weight: 145 lb (66 kg)
Location: Marquette, Michigan USA
Email: woodswoman 2001 AT yahoo DOT com

For the last 19 years, backpacking has become a passion. I am a four-season backpacker and an off-trail navigator. Although I do take yearly trips to the American West or Southwest, the majority of my trips are in Michigan and Canada. My pack weight varies considerably but my base weight is below 14 lb (6.35 kg). I am primarily a tarp camper who averages more than 50 nights a year backpacking in a huge variety of weather conditions including relentless rain, wet snow and sub-zero temps.

Product Information

Hydro-Photon, Inc.
Model Adventurer Opti
Listed Size
15.5 cm (6.1 in) X 3.3 cm (1.5 in) X 2.2 cm (1.0 in)
Tested Size
15.5 cm (6.1 in) X 3.8 cm (1.5 in) X 2.54 cm (1.0 in)
Listed  Weight   3.6 oz (103 g) with batteries
Tested Weight  
3.6 oz (102 g) with batteries
Tested Weight (case)
0.8 oz (23 g)
Model Year 2010

Initial Impressions and Product Description 

SteriPEN Adventurer Opti
The SteriPEN Adventurer Opti arrived in great condition with a neoprene carry case with integrated belt loop, user's guide (written in four languages) and two disposable batteries. There are additional accessories available for purchase, such as a prefilter (if the water source is murky or if I want to eliminate or reduce the amount of floaties in the water).

The Adventurer Opti is a handheld water purifier that works with ultraviolet rays. It is designed to treat up to 1 L (1 qt) of water at a time whenever water is suspect. That could be while backpacking, but it also might be used when one is not familiar with a known pure water source during any travel.

The purifier is designed to be used for clear water but can be used for murky water if it is pre-filtered. The manufacturer claims that the system is easy to use as it involves no pumping, no replacement filters or no chemical taste.

The Opti is small in size making it very convenient to pack. It is about 6.1 in (15.5 cm) long, approximately 1.5 in (3.8 cm) wide and 1 in (2.54 cm) thick. All of these measurements are at the maximum as the shape of the unit does taper. The manufacturer's measurements were the same except their conversions were different on the latter two, hence the discrepancy in metric units listed (see table above).

The handle of the Adventurer Opti is dark charcoal in color with bands of lime green. The rubber-type handle material is very easy to grasp and is not slippery at all. It has handy instructions on the side of it that indicate" Push once for 1 L" and "Push twice for 0.5 L". The push button is located directly below the script, and a LED indicator light is located below the push button.

When I received the Opti, there was a small flap of plastic over the battery area so I took apart the battery end. I then removed the plastic and checked out the compartment. This area can be accessed by turning a single wide screw. It needs to be turned with a coin or screwdriver. Since I happened to have a flat screwdriver handy I used that to open it. There is an o-ring that seals the edge of this area to protect the electronics.

The batteries are commonly found CR123 batteries.
The Opti can be used with either disposable batteries or rechargeable ones. The disposable ones have a life of 100 treatments for a pint of water, for rechargeable ones half that. Battery performance is directly related to temperature, so cold weather will likely cause a performance issue. The manufacturer recommends bringing the unit up to 32 F/0 C before using.

The top end of the SteriPEN Adventurer Opti has a removable clear cover that protects the lamp. The lamp is made out of optical grade quartz and it will provide up to 8,000 one-liter/quart treatments. Near the lamp is located an optical water sensor. According to the manufacturer, this uses proprietary optical water sensing technology. It is a safety feature that is intended to prevent exposure to UV as it only allows operation of the unit when the lamp is completely immersed in water. If the sensor doesn't detect water within 15 seconds of being activated, it will deactivate.
The Opti can also be used as a LED flashlight. That mode is activated by pressing and holding down the single button for 3 seconds. The clear color lamp cover will focus the LED light. It is advised to keep the lamp cover on during use. The blue light that is emitted is not dangerous to look at.

How Does It Work...

The ultraviolet energy emitted by the light is absorbed by the cells of the microbes, preventing them from reproducing. This method has been around for over 100 years but was officially noted by the EPA (Environmental Protection Agency) in 1996: "Ultraviolet (UV) radiation has been found to be an effective disinfectant." 
Reportedly UV destroys viruses, bacteria and protozoa such as Giardia and Cryptosporidium. It doesn't alter taste, PH, or other properties of water. This method is often used in many municipal water supplies as well as by leading bottled water manufacturers.

The Opti has received the WQA (Water Quality Association) Gold Seal that certifies its safety and effectiveness. It also exceeds the "U.S. EPA Guide Standard and Protocol for Testing Microbiological Water Purifiers, destroying over 99.9999% of bacteria, 99.99% of viruses, and 99.9% of protozoa when used as directed". It is also noted that the unit is not a sterilizer.

Trying it out

The manufacturer notes that a water container with a minimum of 1.75 in (4.45 cm) diameter opening should be used. I ordinarily don't use a container with that wide of an opening so I will be changing my style somewhat by bringing a wide-mouth Nalgene bottle. UV-C light will not pass through the container. The container can be glass, metal, ceramic or nearly all plastics but NOT those made from optical grade quartz or some fluoropolymers in the Teflon family. Since most all containers are in the former group there's not much to be concerned about as far as finding a suitable holder. 

There is a plethora of warnings for use on the instruction sheet. These 28 warnings cover everything from not allowing water to enter the battery compartment to not allowing children to use the Adventurer Opti.

I tried using the Adventurer Opti with a 1 L (1 qt) of tap water and everything went as well as expected. At first I thought the green indicator light would never come on but it does takes 90 seconds for that to happen. Here are the steps that I performed:
  1. I filled a 1 L (1 qt) container with water.
  2. I removed the lamp cover by simply pulling the cover away from the handle of the unit.
  3. Then I pushed the activation button once for treating up to 1 L/1 qt of water. (The green indicator LED button near the activation button does flash as well as the white sensor near the lamp.)
  4. I dipped the lamp into the water before the 15 seconds were over making sure the lamp and sensor were completely immersed.
  5. I agitated the water throughout the procedure by stirring it with the lamp until it turned off.
  6. The green indicator LED turned back on to show that the water had been purified.
  7. I removed the Adventurer Opti from the water and dried its surfaces and replaced its cover.


The manufacturer advises keeping the unit in a clean, dry and nonabrasive container. It shouldn't be exposed to temperatures above 140F/60 C or below -4 F/-20 C. The batteries should be taken out if not used for a long period of time.

This is my first experience with an ultraviolet water purifier as I have used only chemical treatment or water filters. As far as weight and packing measurements, the Adventurer Opti fits right in between the other two methods. But as far as speed the Opti has it over those methods. It will purify 0.5 L (16 oz) in 48 seconds and 1 L (32 oz) in 90 seconds according to the manufacturer. I'm looking forward to the next few months of field use as I have a lot of extended trips planned with many types of water sources.

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Field Report:
July 26, 2010

USA Locations and Conditions

During the Field Test period, I have used the SteriPEN Adventurer Opti for all my water purification needs during four backpacking trips totaling 18 days. Locations included boreal and deciduous forest communities, backcountry trails, bushwhacking and more. Elevation ranged from 600 ft (183 m) to approximately 1400 ft (427 m).

Trip 1 - Early April Backpacking Trip:

Location: Pigeon River Country State Forest - Lower Peninsula of Michigan
Type of Trip: Bushwhack 
Distance: Approx 25 mi (40 km)
Length of Trip: 4 days/4 nights

Pack Weight:
31 lb (14 kg)

Sky and Air Conditions: Light snow, cloudy and sunny
Precipitation: 0.14 in (0.36 cm)
Temperature Range: 22 F (-6 C) to 62 F (17 C)

Trip 2 - Late April/Early May Backpacking Trip:

Location: North Country Trail - Lower Peninsula of Michigan
Type of Trip: Trail
Distance: 31 mi (50 km)
Length of Trip: 4 days/3 nights
Pack Weight: 26 lb (12 kg) 
Sky and Air Conditions: Sunny, thunderstorms
Precipitation (Rain): 1.2 in (3.05 cm)
Temperature Range: 52 F (11 C) to 77 F (25 C)

Trip 3 - Mid-May Backpacking Trip:

Location: High Country Pathway - Lower Peninsula of Michigan
Type of Trip: Trail
Distance: 80 mi (129 km)
Length of Trip: 6 days/5 nights
Pack Weight: 32 lb (14.5 kg)
Sky and Air Conditions: Clouds, thunderstorms and sun
Precipitation (Rain): 0.52 in (1.32 cm)
Temperature Range: 34 F (1 C) to 70 F (21 C) 

Trip 4 - Late May Backpacking Trip:

Location: Pictured Rocks National Lakeshore - Upper Peninsula of Michigan
Type of Trip: Trail
Distance: 42 mi (68 km)
Length of Trip: 4 days/3 nights
Pack Weight: 24 lb (10.89 kg)
Sky and Air Conditions: Clouds, thunderstorms and sun
Precipitation (Rain): 0.27 in (0.69 cm)
Temperature Range: 46 F (8 C) to 90 F (32 C) 

Field Work 

No Extra Wait Time

My overall experience with using the SteriPEN Adventurer Opti has been very positive. I love the convenience of it as there is no additional wait time to deal with in comparison to when I use a chemical method. It also weighs much less than a filter plus it is easier to set up. All I have to do is remove the cover and then push the button! Ninety seconds later my water is done. The green LED light has functioned flawlessly to let me know that the water is purified.

With that said, I have had a few experiences where the UV does not fully come on when the wand is immersed in water. Although it does eventually light all the way after perhaps a few more seconds, I am always concerned that the treatment wasn't fully effective. When that has happened, I have retreated the water. This has happened maybe 5 to 6 times overall. With that said, perhaps I didn't have the wand fully immersed the first time or I made some other error that I was unaware of.

Water Sources
The Adventurer Opti in action
I have used the Adventurer Opti during all kinds of weather including inclement weather conditions such as steadily falling rain. It was easy to use and I was glad that I didn't have to deal with waiting times,etc. Although I don't have temperature readings from the various creeks, rivers, lakes, etc. that I treated water from, my best guess is that they were anywhere from just at freezing (0 C) to about 45 F (7 C). They simply didn't warm up that much since early spring.

Although my water sources varied with location, all of them appeared mostly clear. I didn't have to use any murky or silty-type water. Types of water sources included rivers, creeks, small lakes and the gigantic fresh water lake, Lake Superior.

Some of my water had small floaties but nothing that needed to be strained. I didn't feel that a pre-filter was necessary for my sources although I understand that there is one available from the manufacturer for such purpose.

One property that I was very aware of was the fact that the Adventurer Opti does not alter the taste of water. Even though all of my water sources were fairly good tasting, I was much more aware of the individual-type taste of each source in contrast to when I used to treat it with chemicals (chlorine dioxide) where they all seem to taste similar because of the chemicals.

I have altered my style somewhat as I am now carrying a wide mouth 1 qt (1 L) container to treat the water. I still carry two 1 L (1 L) flat hydration bags to drink the treated water from but they are small mouth. They likely wouldn't be the best containers to treat the water, as the wand needs to be agitated within and the small opening is inadequate.

Because my usual method is chemical treatment where I rinse the threads of the bottle after treating (to cleanse), I wondered how that would translate to a UV method. I have continued to do that but I also realize that no water treatment method is perfect. I readily assume that the less than 1/10 of one percent of error is likely not going to make me sick.

No Guarantee That it Will Kill Worm Eggs

As stated above, the SteriPEN Adventurer Opti was used during 18 days of backpacking during the field testing period which lasted over three months.
I also took an additional backpacking trip of 8 days during the Field Test period where I couldn't use the Adventurer Opti. The area I was backpacking has the potential to have tapeworm eggs in the water sources. I contacted SteriPEN to make sure that their recommendations on the website were still accurate for worm eggs. A representative responding by saying that. "Studies have indicated that the UVC light that the SteriPEN emits had a disinfecting effect on worm eggs. Unfortunately, we can not vouch for this, because we are not inclined to do any tests that involve animal testing, as testing for tapeworms would require us to do". Although I would of loved to used the Adventurer Opti on that trip, it wasn't in my best interest.

Battery Life
Normally I purified approximately 4 qt (3.79 L) of water per day for my drinking and cooking needs on each trip. This amounts to approximately 72 qt (68 L) of water that was purified using the Opti. This is well past the expected battery life of 100 pints (47 liters) or 50 quarts (47 liters). I have not become ill from the water that was treated but I realize that my statement is purely subjective as I may not have become ill anyway. Regardless, I am pleased with the outcome.

I haven't used the flashlight option as much as I would have thought. I guess I am concerned about it wearing down the batteries (even though I carry extra). It is a great light source however and I did use it during a big rainstorm when I needed a better light source than my 6 V headlight. Since I live in a very northern environment it also stays light out until at least 10:30 PM at night not necessitating much camp usage. 
In the Long-Term testing period, it will start getting darker earlier so I plan to use it more in the evening at camp when needed. I will try to monitor its effect on batteries.

Durability and Care So Far

The Adventurer Opti has proven to be a dependable unit through the first three months of testing. I don't consider the slight problem earlier mentioned to be much of a concern. Its convenience, weight and usability are very functional for my active travel in the bush. There has been little care involved other than wiping it off after immersion and using the neoprene sleeve to store it. It fits handily in the outside pocket of my various packs so that I can use it on the fly.

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Long Term Report:
September 27, 2010

USA Locations and Conditions

During the Long Term test period, I have used the Adventurer Opti during four more backpacking trips (22 more days) in diverse locations. Locations included those in Michigan, Colorado, and California, USA. Elevation hiked ranged from 600 ft (183 m) to 13,000 ft (3962 mi). Terrain included two trips to a sandy island at sea level to mountainous rocky terrain at high elevation in two western states.

Trip 5 - Early August Backpacking Trip:

Location: Grand Island National Recreation Area - Upper Peninsula of Michigan, Lake Superior
Type of Trip: Trail
Distance: 12 mi (19 km)
Length of Trip: 3 days/2 nights

Pack Weight:
24 lb (10.89 kg)

Sky and Air Conditions: Sun, clouds and rain
Precipitation: 0.32 in (0.81 cm)
Temperature Range: 64 F (18 C) to 82 F (28 C)

Trip 6 - Late August/Early September Backpacking and Day Hiking Trip:

Location: Colorado (Maroon Bells-Snowmass Wilderness, Aspen; Glacier Gorge and Bear Lake Trails, Rocky Mountain National Park)
Type of Trip: Backpacking, Day Hiking
Length of Trip: 8 days
Pack Weight:
28 lb (12.7 kg)

Sky and Air Conditions: Sun, clouds and rain
Precipitation: 0.11 in (0.28 cm) rain
Temperature Range: 86 F (30 C) to 36 F (2 C)

Trip 7 - September 9 -10 Backpacking Trip:

Location: Grand Island National Recreation Area - Upper Peninsula of Michigan, Lake Superior
Type of Trip:

Distance: 11.7mi (18.8 km)
Length of Trip: 2 days/1 night

Pack Weight:
22 lb/10 kg (includes 4 lb/1.8 kg of water)

Sky and Air Conditions: Cloudy
Precipitation: None
Temperature Range: 56 F (13 C) to 41 F (5 C)

Trip 8 - September Backpacking Trip:

Location: Yosemite National Park, California
Type of Trip: Trail - High Sierra Route
Distance: 71 mi (114 km)
Length of Trip: 9 days/9 nights

Pack Weight:
25 lb (11 kg), had one food drop to lessen load

Sky and Air Conditions: Mostly sunny
Precipitation: None
Temperature Range: 85 F (29 C) to 28 F (-2 C)

Field Work 

During the Long Term period I have had continued success with the Adventurer Opti. Just when I thought the batteries would never wear out, my first attempt in Colorado indicated a red signal after immersing the unit in water. I retried it a few times with the same result so I changed the batteries. It ran perfectly again!

All of my water sources have been clear looking so I haven't had to use a pre-filter although I carried some coffee-type paper filters for that purpose. I realize that there is a specific pre-filter that can be purchased to use in conjunction with the Opti but I haven't felt it to be necessary.

During the Long Term period I also used the Opti in colder weather with temps down to 28 F (-2 C) in the High Sierras of California. Since I stored the pen in my backpack, the unit itself probably didn't get quite that cold and it worked fine every time I used it.
Using the Ziplock container to purify water at Fletcher Lake in the High Sierras
For simplicity purposes I decided not to carry my heavy wide-mouth Nalgene water container but instead to save weight I used a plastic twist-on top Ziplock container (that I carry anyway to store my crackers or pretzels). I kept the food contents in a zip bag inside the container so that when I am not using it to treat water they can be stored safely. This has worked out well.

On one of my short trips to a nearby island I forgot to take the container so I thought I might be up the creek so-to-speak. My small-mouth collapsible bottles weren't really suitable. The best I could do was to use my cook pot. Since I hadn't used that before for that purpose, I hoped it was safe. Most metals, plastics, etc are deemed appropriate containers so I went ahead. All was well but I missed my regular container. I made sure I packed it on my next trip which lasted nine days.

With less daylight hours lately, I have also used the flashlight feature of the Opti during my last two trips. It has worked well but I was surprised when the light goes out after a few minutes. This is not a big deal but I didn't anticipate that it had a timer. Further experimentation revealed that the light is good for 3 minutes before it has to be reactivated.

Backtracking to my Field Report, I did notice that the website has recently changed its wording regarding the effectiveness of the SteriPEN against worm eggs. It's a better statement that leaves no doubt that the company "cannot give a definitive answer" as they don't test worm eggs. I think this makes it much clearer to the consumer than the previous wording.

Durability and Care 

The Adventurer Opti looks as good and performs as well (total of 40 field days of testing) as it did when the testing period began. I always use the neoprene sleeve to encase it with good results. It's just an extra measure of insurance that I won't accidentally damage it.

Final Thoughts

I have been very pleased with the Adventurer Opti. Not only has it been simple to use but it is easy to stow. I have continued to be healthy so I would like to think that it helped me from obtaining any water borne illnesses.

  • Durable
  • Easy to use and simple to care for
  • Long life to batteries
  • Worked well in a variety of water sources including creeks, rivers, lakes and an inland sea (Lake Superior)
  • None

Tester Remarks 

Thanks to SteriPEN and for this opportunity to test the Adventurer Opti. This concludes my Long Term Report and the test series. 

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Read more gear reviews by Gail Staisil

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