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Reviews > Cook and Food Storage Gear > Cooking Accessories > FLEJ Solo Cup > Test Report by Will Dalen Rice

October 12, 2008



NAME: William Rice
AGE: 27
LOCATION: Charlotte, North Carolina, USA
HEIGHT: 5' 7" (1.70 m)
WEIGHT: 145 lb (65.80 kg)

I began backpacking at the age of 13 when I first went to summer camp (1993). In 1999, I started working with a college tripping organization in outdoor trip logistics (in gear preparation), and then as a leader. My most frequented hiking locations are in the Carolina Appalachians and the Smoky Mountains during the cold early spring and the summer. I stopped being a trip leader in 2004, and now I average about 4 backpacking trips and 4 day hikes per year. I carry between 25 and 35 lbs (11.3-15.8 kg) on multi-day trips.



Manufacturer: Flej
Year of Manufacture: 2008
Manufacturer's Website:
MSRP: GBP 7.50
Listed Weight: not available
Measured Weight: 90 g (3.17 oz)
Listed Volume: 300 mL (10 oz)
Measured Volume: 260 mL (8.6 oz)
Dimensions: Cylindrical with Length 4.25" (10.75 cm) and Width 3" (7.59 cm). The cup is slightly larger in diameter at the top than the bottom.
Lid Details: The lid is round and presses onto the cup (does not require screwing). There is a rubber gasket that seals the lid to the cup. The drinking opening is raised and square, with rounded sides. There is also a vent to prevent gurgling.
Sleeve Details: The neoprene insulation sleeve is sewn together with a single line of stitching. It appears to be about an 1/8th of an inch thick (0.32 cm).
Agitor Details: The bottom part of the cup is the Agitor mixing contraption. It has a raised center at the bottom of the cup to allow the button to push upward into the drink. As it does so, the liquid in in the agitor chamber is forced out into the cup through helical slits, causing a swirling motion of the liquid.



My initial impression is favorable. The cup is lighter than I expected. It is also small enough that I changed my mind and now plan on cramming it into my already full backpack for a 17-day Appalachian Trail hike. I am anticipating drinking some hot drinks at breakfast while in the backcountry.

The cup is made of clear plastic, with a very small and hardly noticeable single seam. The cover is made of neoprene with a single stitch line. The lid and the base are made of a darker plastic that looks to be denser and stronger. The button on the bottom is made of rubber. There is also a gasket around the lid, to keep the top sealed to the cup. The top presses on to the cup and the base screws on to the cup.

On the bottom of the cup, it has the recyclable logo with "PP/TPE," meaning Polypropylene and Thermo Plastic Elastomer.

The cup is advertised to be dishwasher and microwave safe.


The only instructions on the package are that one simply has to use a finger to pump the bottom for easy stirring. On the bottom of the cup (not to be read while it is full) it has an arrow for tightening the base after dishwasher use. Operation was very self explanatory to me.


Tea and Honey (in microwave)

My first trial was with a cup of tea and some honey. I put the whole cup (with sleeve) in the microwave (no lid) to heat the water. No damage was done. Once the water was warm, I put the honey in. I have some honey that has become rather granulated, so the clump went straight to the bottom. Then, I pumped the Agitor about 20 times and the honey was completely dissolved. I could visibly see also how the water was swirling. Then, I put a tea bag in and pressed the lid on. I waited about 5 minutes, pumped the Agitor a few more times, and the tea was ready. It tasted well mixed and was as hot as it came out of the microwave.


This time, I poured the powder into the cup, and added already heated water. The oatmeal kept warm and I could not feel any heat through the sleeve. I pumped the Agitor a couple times just to stir up the bottom. There was no unmixed oatmeal. It was easy to eat and the Agitor did not get stopped up from the oatmeal flavor powder (my original expectation).


The first time I used the cup, it tasted funny. I assumed this was the tea. The same flavor was there for the oatmeal. I realized that it was probably the plastic, and that it needed to be washed better than the rinse I had given it. So, I put it in the dishwasher. I was unable to remove the screwed on bottom. I did remove the neoprene sleeve from the cup. I find it easy to remove and replace. The cup came out of the dishwasher unharmed and without the chemical smell.


I plan to take this with me on the Appalachian Trail in Georgia and North Carolina (USA). It will be in the woods with me for 13-17 days, being used in the morning for breakfast and maybe at night for a hot drink.


The cup has worked well so far. It has lived up to its claims and looks like it's going to be a fairly useful tool. Its durability will be tested through some constant use in June.

- Light
- Easy to use
- Effective (so far)

- Chemical smell/ taste that required REAL GOOD wash to get rid of
- Can't unscrew base



June 5th and 6th
Location: Southern Appalachian Trail, Georgia, USA
Weather: clear to partly cloudy skies, 70-85 F (21-29 C)
Elevation: 2000-3000 ft (606-909 m)
Terrain: Very rugged, trail very difficult

The FLEJ cup came with me on a short Appalachian Trail hike. It spent 2 days and 2 nights with me in Georgia's (USA) southern Appalachian Mountains. The weather was not as cold as I had expected, so the need for a hot beverage was limited.

I used it once to make hot chocolate. It mixed the chocolate well, but the serving size seems really small to me. My meal portions were large, so it was not practical for me to use the cup as a bowl also.

After June 10
Location: Home use
Activity: I have been using it as a "special feature" dish around the house.


Hot Chocolate: at least 5x
I have been making the kind of hot chocolate that has marshmallows in it. There are two ways that I make it. One way is to heat the water independently in the microwave. Then, I add the powder mix to the hot water. At first, I was wary of putting the neoprene sleeve in the microwave. I removed it, but then found it hard to reapply while there is liquid inside (spilling occurred). Then, I tried putting the whole thing in the microwave. There were no adverse effects. When I was pumping the button to get it to stir though, I felt very much the temperature of the liquid through the button. When the liquid was REAL hot, I did not want to burn myself pumping the button. With the powder added to the top of the hot water, it took way more pumping than seemed practical (40+ pumps). I think the best way to pump is to place it overhanging from a counter, to keep it steady. Otherwise, I feel like a lot of my upward pushing moves the whole cup and in some cases causes spilling. I got tired of pumping the button and started drinking. There were still a few floating clumps of unmixed cocoa. These clumps eventually stuck inside the lid and were hard to clean out because of their location inside the spout.

Hard To Clean Nooks

It worked much better when the water was added to powder mix already in the cup. The pumping still seemed like a lot (20+ times), but something I could get used to. It did completely mix this way, and thus was no problem cleaning.

Hot Tea: at least 5x
As I mentioned, heating water in the microwave works well. Then, its just a matter of putting a tea bag in the cup. The lid can still be placed on with the string hanging out. This does not compromise the seal. The tea stays warm, and is easy to drink through the spout. Adding honey before or after the hot water works and mixes easily with the Agitor. I left a cup full of water and a tea bag to brew over night, and still the cup did not retain the flavor of the tea.

Red Seal


Other notes:
There is a vent on top of the spout, near the drinking opening. It appears to be an air opening, so suction doesn't build up and cause gurgling while drinking. However, when I drink, I end up putting my mouth over this opening because it is close to the spout. A little gurgling doesn't really make a difference anyway, but if that's the point of this feature, it doesn't work.

Date: July 31
Location: In the car
Weather: 90 F (32 C)
Elevation: NA
Terrain: bumpy
Activity: I was interested in how this "travel mug" works in my car. So, I brought it with me on a bunch of errands.

I filled the cup with ice tea and an ice cube. I noticed that at the end of my drinking the ice tea, the cube was still in the cup and I was still thirsty. With such a small capacity, giving up liquid for ice is a choice I will not make again. The cup was filled to the brim and then the lid was placed on. It fit fine in my cupholder. The tapered shape of the cup actually helped it to fit tight in both my cupholders, which are different sizes. I drove around as planned and the cup did not spill when I hit potholes or went over speedbumps. However, I did pull out of a gas station with a slight decline and tea came out of the spout opening. I drove around for about 2 hours with 4 stops for about 20 minutes each. My tea stayed cold and I drank it when I got home.


Total Uses: 20+ times (Hot Chocolate, Hot Tea, Ice Tea, Oatmeal)

I have found the Flej cup to lack versatility for my personal use, and therefore I will be less likely to use it on light backpacking trips where I am really trying to cut weight and only carry essentials. It does work well as a travel mug, as long as I am not looking to drink a lot, as the capacity is small. It will keep a hot liquid hot without burning your hands, thanks to the neoprene sleeve.

- lightweight
- insulated well to keep liquid warm or cool
- does not hold flavors

- mixer takes a lot of pumping
- not big enough

Size compared to hands

- I still can't get the base to unscrew

Can't Unscrew


I will take the cup on some more outdoor trips, including but not limited to 1) some day hikes and 2) some overnight backpacking/ camping trips.

I am also interested in answering the following questions:

Will the cup eventually start to retain flavors?
What about coffee?
Will I ever be able to get the base unscrewed?



Location: Travel Mug

I have continued to use the Flej as a travel mug, in my car, driving to and from work or wherever. It keeps tea plenty warm and is easy to drink from. When I was concerned about spilling, I did not put more than 8 oz (236 mL) in the cup. Having the cup more fill than that can cause spilling in bumpy conditions. It also fits very securely in my shallow cup holder and my deep cup holder.

Date: October 3rd and 4th
Location: Mountains to Sea Trail, Marion, NC, USA
Weather: 37-73 F (2-22 C), Clear Skies, 74% humidity
Elevation: 1395 ft (465 m)
Terrain: Mountainous

I went for an overnight backpacking trip. The cup came with me. In the morning I made hot tea to drink in addition to having a breakfast of oatmeal. The tea stayed warm, I didn't feel heat through the cup and sleeve, and it was easy to drink when I was ready for it.


The Flej cup has shown only minor signs of wear and tear. The neoprene sleeve is beginning to get a little dirty and pick up particles of random things and lint. The lid and base have some scratches, from falling off rocks and whatnot in the woods. The exterior also got beat up a little in my car, when I left it on the floor and it rolled around a little during non-use. The seal however, has no signs of deterioration and neither does the Agitor.

I finally got the base to unscrew. This was quite frustrating for me. I don't brag about my strength, but I am fit enough to open anything my girlfriend gives to open. I was not able to unscrew this base the first 10 times I tried. Maybe there is some trick I could have done, but just gripping and turning was unsuccessful for a long time.


The cup works fine as a cup. I still feel like its a little heavy for a backpacking cup. The stirring feature also does not really capture me past the initial review. It seemed to me like a great novelty product. But, I have come to believe (and notice) that any situation where I have the cup and a hot beverage, I also have a spoon. This sort of negates the usefulness of the stirring device, and really just make the Flej another travel cup (which it works fine as). Personally, I tend to drink liquids (hot or cold) in larger quantities as well, so the Flej comes up a little short in that respect.

- easy to clean (disassembled or not)
- does not hold flavors
- easy to hold, good grip
- does not spill under normal conditions
- watching the liquid swirl when I furiously pump the Agitor
- durability: the Flej cup has shown minor signs of wear and tear
- the plastic has done an outstanding job of not holding flavor. I have left it with a little bit of tea in it for a couple days, resulting in fermentation, and was still able to rinse it well and drink out of it

- too small
- too heavy


As I mentioned, I believe it is a little too heavy and bulky for serious use as a backpacking tool. Also, I do not tend to bring hot liquids with me in the car a lot, so probably will not continue doing that either. I have a friend who is interested in using it with his French press coffee, so I will likely lend it to him, and if he enjoys it, let him keep it.

This report was created with the Report Writer Version 1. Copyright 2008. All rights reserved.

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