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Reviews > Cook and Food Storage Gear > Cooking Accessories > FLEJ Solo Cup > Test Report by Peter Spiller

Flej Solo Cup

A Test Series by: Peter Spiller

Intial Report May 28, 2008:  Tester Information
Field Report (August 1, 2008) Product Information
Long Term Report (October 8, 2008)

Tester Information:

Name: Peter Spiller Backpacking Background: I have been camping and hiking avidly since childhood.  In the last several years my passion for backpacking and kayaking has grown.  I am a Chapter Outing Leader for the Sierra-Club, I have trained in Wilderness First Aid, and am a staff member for a Wilderness-Basics course.  I enjoy solo backpacking and group trips.  I have an adaptable style that is fueled by my interest in backpacking gear.  I pack as light as possible when the situation dictates, but I am not against hauling creature comforts. I average 1-hike a week, and 1-backpack a month year-round.
Age: 38
Gender: Male
Height: 6 ft 0 in (1.83m)
Weight: 190 lb (86 kg)
Email address:
City, State, Country: La Mesa, CA U.S.
Personal Website:

Product Information:

Manufacturer: SedgeWarbler
Flej Solo Cup
Manufacturers Website:
Model: Solo Cup
Measurments (Manufacturers): Height: not listed
Diameter: not listed
Weight: not listed
Measurments (as delivered): Height 4.2 in (10.7 cm)
Diameter: 3.25 in (8.26 cm)
Weight: 4 oz (113 g)
Volume (manufacturers): 10 fluid oz (.3 L)
Volume (as delivered): 10 fluid oz (.3 L)
Model Year: 2008
MSRP: 7.50
Manufacturers Description:
From Website: Flej Solo is the ultimate outdoor and travel cup. The neoprene sleeve will keep a drink hotter for longer and comes in a range of funky colours. The lid has a specially designed spout which, when sucked on, will activate the Agitor Micro Pump and mix the drink. Beats trying to remember where you packed a spoon or stirring with a stick.
Infinite Guarantee
From Website:We believe so strongly in the quality of what we make that if, at anytime, our product fails to meet your needs, we are happy to exchange or return it. Because of this solid belief, our products are guaranteed forever and are designed with this in mind. Your total satisfaction in our product is our goal.

Initial Report:

May 28, 2008

Product Description

packageThe Flej Solo Cup is a fluted plastic mug with a lid and a neoprene sleeve that functions as insulation. There is a substantial spout opening in the domed lid, with a small vent adjacent to it.  The lid is made of an opaque grey plastic, while the cup portion is made of a translucent white plastic.  The cup is small and compact with no protruding handles or parts.  It fits well in my hand, and the neoprene sleeve conforms to the fluting of the cup to make it easy to securely grip. The neoprene insulating sleeve in my particular cup is red with a substantial seam sewn with black thread.  The  Flej logo is silk screened on one place on the sleeve in white.

Initial Impressions

Upon receiving the cup, I proceeded to open the package and inspect the cup and lid.  I was impressed at the apparent quality of all of the components.  No defects were found on my initial inspection.

I was unable to find the volume of the cup previous to receiving it in the mail.  The cup was smaller than I anticipated.  The packaging lists the volume at 10 fluid oz (.3 L) and upon measuring it the volume is correct. I found it impossible to fully utilize the full 10 oz (.3 L) as it fills the cup up to where the lid attaches, spilling out some of the contents when the lid is pressed in.  I speculate that the compact size is ideal for my backpacking trips, and will report on this in the field report.

The packaging and website for the cup touts the built in stirring feature of the cup referred to as the “Agitor”.  Upon inspection of this feature, I was very impressed as to the engineering that went into this feature.  The stirring feature resides on the bottom of the cup, and is activated by pressing a rubber button recessed into the base or sucking on the lid.  When the buttonis pressed, it squeezes liquid through a series of channels built into a plastic dome above the button that create a small whirlpool in the cup; stirring the drink.

"agitor" micro-pump

The lid fits well, and seals nicely with the cup using a series of soft rubber gaskets.  The lid appears to be secure, although the drinking hole is larger than any I have experienced.  This leads me to speculate that it will spill easier than the mugs I have previously used.   I will report on this as I gain experience.

Initial Use

Upon receipt of the mug, I was intrigued by the stirring feature,  so I put a little water in the base of the cup,  and placed a few small blades of dry grass into the cup to test the action of the “Agitor”.  When I pressed the button on the bottom of the cup several times, the small blades of grass began to swirl.
frayed edgeThe cup I received had a distinct plastic odor when I received it.  The Flej website instructed to thoroughly wash the cup to remove the odor.  I disassembled the cup removing the lid and the neoprene sleeve in preparation for washing.  I then tried to remove the base in which the “Agitor” is contained and was not successful.  I consulted the directions and was assured that the base was removable but only recommended for thorough cleaning; so I stopped trying.  It was only after washing it the first time that I was able to successfully remove the base.  After the cup was dry I reassembled the components, struggling to get the neoprene sleeve back on, slightly fraying the edge in the process.

With the cup clean, it was now time to pour in my first cup of coffee with a little creamer.  Both my wife and I looked in anticipation as I pushed the “agitor” and were rewarded with a dramatic swirl of the creamer, and the almost instantaneous blending of the dark coffee and  light creamer.  I proceeded to drink my well-mixed coffee and creamer with pleasure.

Agitor Through LidImage courtesy of

Quality Assessment

The Flej Solo cup by all appearances is a high quality product.  It seems to be well designed and well-built using sturdy materials throughout.  My initial struggle with the insulating sleeve  and the subsequent fraying of the edge has me a little concerned with the durability of this component, and I will give full details during the field report.  The lid and the base fit very well in the cup and create a tight seal with no leaking at this point.

The real quality is apparent in the design.  The details I find examining the cup over the course of the last couple of days have highlighted the engineering that went into the design to make it a viable camping travel mug.   The compact size with no protruding parts, along with the simple but effective construction of the stirring mechanism make me excited to further test this cup on my adventures over the next four months. 


 Field Report

August 1, 2008

Flej Solo Cup in all its glory

The Flej solo cup has been my constant companion during 15 days of camping thus far this summer. I have used the Flej Solo cup as my primary drinking vessel while base camping as well as backpacking.  The cup has seen a variety of beverages including coffee, tea, lemonade, wine and water.  The cup has been used for an extended period in the field with only limited maintenance and cleaning.  The following is my report on its performance.

Field Locations:

Silver Lake- June Lake loop Sierra Nevada Mountain Range, California- 8days June/July 2008

Elevation: 6772 ft (2064 m)
High Temperature: 90.2 F (32.3 C)
Low Temperature: 41.6 F (5.3 C)
Precipitation: .02 in (.5 mm)

The Flej solo cup primarily served as my morning coffee cup, and my evening tea cup while base camping on Silver Lake.
Twin Lakes- Mammoth Lakes, CA -5 days July 2008

Elevation: 8202 ft (2499 m)
High Temperature: 83 F (28.3 C)
Low Temperature: 44 F (6.7 C)
Precipitation: 0 in (0 mm) (while no precipitation was recorded, the location we camped received several seasonal thunder storms that dropped more than a trace amount of precipitation.

Again the Flej solo cup primarily served as my morning coffee cup, and my evening tea cup while base camping at Twin Lakes.
Heart Lake- Little Lakes Valley, CA- overnight July 2008 1-day

Elevation: 10300 ft (2064 m) at trailhead
High Temperature (approximate): 80 F (32.3 C)
Low Temperature (approximate): 40 F (5.3 C)
Precipitation: trace amount (a short evening thunderstorm dropped rain for about 30 minutes)

The Flej solo cup was the only drinking vessel I had during this backpacking trip.  I brewed tea in it during the evening and for breakfast, as well as using the cup for water while in camp.

Three Sisters Falls- San Diego County, CA July 2008 1-Day

Elevation: 2800 ft (853 m) at trailhead
High Temperature (approximate): 90 F (32 C)
Low Temperature (approximate): 55 F (13 C)
Precipitation: 0 in (0 mm)

The Flej solo cup was the only drinking vessel I had during this backpacking trip.  As with the previous trip I brewed tea in it during the evening and coffee for breakfast.

Field Performance

The Flej Solo Cup has worked solidly as a camping/backpacking cup.  I have used it extensively, and it had proven to be functional and durable.

During one extended trip in June and July, I used the cup daily for 14 days without having the opportunity to disassemble the components of the cup and thoroughly clean them. Cleaning consisted of rinsing the cup with clean water, pumping the “agitator” a few times, pouring out the water and rinsing a second time.  The cup held a variety of liquids during this trip, and I did not notice any flavor cross contamination as long as I rinsed the cup after use.  When I arrived home, the exterior of the cup was very dirty, and I found that there was some build-up on the internal components when I disassembled the cup.  I put the plastic components in the dishwasher, and washed the neoprene sleeve with warm water and dish soap, which returned the cup to a respectably clean condition.

Before leaving for my first camping trip, I tried activating the “agitator” feature by sucking on the spout as indicated in the directions.  I was very hesitant to do this initially with hot liquid in the cup, so I initially tested it with cold water.  I was able to activate the mixing feature this way but I needed to apply more suction than I expected. While no water splashed up onto my lips, I am still hesitant to mix my hot beverages using this method, and almost always mix them by depressing the rubber button on the bottom of the cup with my finger.  I wondered how useful the mixing would be for me as I drink my coffee black, and do not add anything to my tea.   I did find that using the mixing feature while brewing tea speeds up the process significantly by forcing the water through the teabag.

neoprene sleeve wearThe neoprene sleeve works well to keep my beverage warm or cool for a reasonable period of time.  It also has insulated my fingers from the heat of the hot beverages while gripping the cup. As it is summer, I have not had the opportunity to use the cup during temperatures colder than 40 F (5.3 C) and cannot comment on whether the neoprene insulation will work as well in colder weather.  The sleeve has held up decently during 15 days of use, although the edges of the sleeve have sustained more areas that are frayed or pulling apart. There is one small nick in the sleeve; probably as a result of the many times I have tightly packed the cup in various backpacks and daypacks. The lid has a few minor scratches.  At this point all of the wear is cosmetic.

The design of the cup for me has proven to be a compromise of size, shape weight and capacity.  Initially I was concerned that the cup was too small, and was disappointed that the 9 oz capacity would not work for me as an every day “commuter” cup.  Upon reflecting on my use of the cup as a camping and backpacking cup I have accepted that this cup was never intended for everyday use, and the volume and shape are designed for the size constraints imposed when backpacking.  The 10 oz (.3 L) capacity has worked in the more relaxed environment while camping where I can just reach out to my stove and refill the cup.  The ovoid shape with no extruding parts make it easy to stuff into a tight nook in my backpack without worrying about breaking or bending any of the components.  The plastic smell and taste initially encountered when the cup was new have completely disappeared, and at this point I cannot detect any taste or smell coming from the plastic components.


The Flej Solo Cup has performed well in two months of testing.  It has come through 15 days in the field with what I deem an acceptable amount of wear and tear; all of which is cosmetic and does not adversely affect the performance of the cup.

The worst I can say about the Flej Solo Cup, is that it has somewhat of an identity issue among my backpacking gear.  When I am packing for a “light and fast” minimal trip, the built in stirring feature (agitor) seems like a way to save weight, but I already carry a spoon that would accomplish the same task.  A cup without the “agitor” would be slightly lighter, without the added redundancy; better fitting my “light and fast” philosophy.  When packing for trips where comfort is more of a priority than weight and volume,  I would prefer to pack a cup with a larger capacity. I would like to have two separate versions , one ultralight version without the stirring feature,  and a larger version with the “agitor” built in.

Please check back in about two months when I report on the performance of the Flej Solo Cup after four months of testing.  Thank you Sedge Warbler and for the opportunity to test this fine cup. 


Long-Term Report

October 8, 2008

Field Use:

I have not had the opportunity to test the Flej Solo cup as extensively during the long term testing period as I had during field testing.  With this said, the cup did see two days and nights of use while camping at the Julian Starfest in Julian California. During the total duration of the test, I have had the opportunity to use the cup for 17 days in the field.

Julian Starfest, Julian, California

I have used the cup on two evenings while camping in Julian California as part of the annual Starfest.  The weather was mild with clear skies and no precipitation.


High 84 F (29 C)
Low  56 F (13 C)

Long Term Impressions:

I used the Flej solo cup as my primary drinking vessel while camping.  The cup held coffee, tea, wine and water at various times in the two days of camping.  The only form of cleaning was a cursory rinse and shake with clear water.  I did not have the opportunity to clean the cup thoroughly after the trip, and it sat in my supply box for several days before being cleaned at home.   When I did clean it, I noticed that it had coffee build-up in the “agitor” feature.  I struggled to remove the base, and it was only after several minutes of trying, and finally rinsing the base in water and letting it sit for several minutes that I was able to unscrew the base to thoroughly clean the components. A trip through the dishwasher returned the plastic components to a pristine state.  The neoprene sleeve remains in good condition although it does bear the faded marks of a well-used coffee cup.

A Well Used Cup

After four months of testing, and 17-days in the field using the cup in a variety of different situations, I am confident in saying that the Flej Solo cup performs its job solidly, and I predict will last me for many more trips to come.  The durability of this cup is outstanding.  Even the potentially vulnerable rubber on the base that comprises the “Agitor” feature is still pristine. The neoprene sleeve shows wear, but none that I would consider abnormal for the number of times I used the cup.  The mixing ability remains effective and convenient. With that in mind, I still am firm in my assertion that the identity crisis that I wrote about in the field report is still evident.  This cup would be outstanding if it did not try to do so much.

Continued Use:

I will continue using Flej as a cold weather cup.  The compact size, and the insulating neoprene sleeve make this the best cup I have when the weather is cold. The ability to keep a beverage warm justifies the small weight penalty this cup entails.  For “light and fast” trips, I will be returning to my titanium cup, as it provides all the features I need in a cup,  and I am not carrying redundant weight.   I would purchase and use a Flej cup with the “agitor” feature and use it daily if at some point they designed one as a commuter mug, with a larger capacity, a more spill-proof lid, and a handle.


During the 17 days of use, I have been happy with the performance of the Flej Solo Cup.  It is a solidly performing cup, and has not had any major issues to date.  The plastic is durable, the neoprene sleeve insulates the contents, and the “agitor” stirring feature works as advertised.  The compact shape makes it easy to pack.  The capacity of the cup makes it impractical as a daily commuter mug, and the “agitor” feature is redundant when you are carrying an eating utensil.  I have enjoyed using the Flej Solo cup, and will continue to use it in the future in selected situations.

This ends my test of the Flej Solo Cup.  I want to thank Sedge Warbler and for the opportunity to test this great cup.


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