Made for more than 2 gallons
348883
I put mine in my 1.75 gallon glass urn, it got so hot it killed my betta that I've had for a long time just overnight. So it's safe to say I'm not happy with it. I would suggest putting it in at least a 2 gallon tank seeing that it gets so hot and you can't adjust the temperature.
4135489
The filter displays an unintelligible number that doesn't reflect gallons. I don't know when I have reached 200 gallons so I can change the filter. It guess it could be the actual filter that does this, but either way it is a pain.

Update I have replaced the filter with a new one and it reads 830. I know I haven't used 830 gallons of water in less than one month. I fill up my coffee maker with 2 qts every two days, which is about 15 gallons per month.  What the heck is that number and why is it so high?
2921836
Protip: Empty the filtered water into gallon size jugs and keep the container empty of water /most/ of the time. I have found this extends the life of the filter for maybe double the number of gallons.
1913440
The product is well made and will last a long time. But for a 10 fall in tank it's a bit big. You have to use an up and down motion to start siphoning the water and you don't have the room to do it. I would get one that has a value.
448546
So other places prices were way high, I took a chance and they came before they the expected time. They could be a little stronger, 1 bottle says it will flavor 5 gallons, I would say it does 4 gallons ... but for the price it was worth it. I will buy again
1247948
Holds more water than the pitchers and has a spout.
4219116
Have gone thru 2 gallons so far and will be getting the 5 gallon next time. Hard to tell how it works until a few years pass but, so far so good.
4693251
Make sure you check the dimensions.  I didn't think the 2.7 gal was a large as it is.  I planned on putting it in the back of the cabinet under my sink, but it just couldn't quite fit around the pipes.  It still fit in a more up-front part of that cabinet.  It was an easy install, and startup process.
2756995
Came well packaged and sealed. The filters are reusable until 18.5 gallons have been filtered. That's quite a lot of water. Keep in mind, the water needs to be reasonably clear to begin with. These simply fight against bacteria, viruses and water borne diseases. But too much silt or sand will clog them readily. Consider 18.5 gallons could easily support one person for over a month at the suggested 64 oz. a day. One filter could last one person twice as long as that in a rationed situation. All in all, an excellent purchase for emergency supplies. I received this product at a discount for my honest and unbiased opinion
4027030
+Brand new
+Holds 2.5 gallons
+Fits in the fridge
-Leaks after less than 2 months
-Waste of money
-TRASH

Spend a few extra dollars and buy a better quality one. Before I threw it in the trash, I noticed two spots that look like they're going to crack and leak in more places.
3989270
I suppose the No-Spill 1405 2-1/2-Gallon Poly Gas Can (CARB Compliant) could be made with a longer nozzle but it might prove to be kind of a space hog.  This device solves that problem efficiently.
4570787
Works great in my little 1/2 gallon. I put it on a timer to go off/on hourly so it will not overheat.
4742368
Good deal for 2 bottles with filter inside and 2 additional filters.  Only complaint is that when you get close to the bottom of the bottle it is a little hard to get the water out.

Fill it a couple times of day...leave it in the refrigerator and have it already to go.

Water Tastes Fine.
1081874
I don't know why there are so many bad reviews for this product. I have used them for several years and had few problems. I have mostly used it for 2 gallon tanks and it does nicely. I would not use it for a 1 gallon or for above a 3 gallon. I've used it for bettas and dwarf shrimp. They do require rinsing from time to time and you might have to open it up to give a thorough cleaning. I have used it with the spray bar and direct flow attachments. I don't like the spray bar. To decrease the flow you can stick a teeny bit of aquarium floss in the flow attachment or cover it with a piece of pantyhose. Or just face the opening towards the wall. Overall I like this filter for a smaller tank.
1007291
This is perfect for our needs.  The larger capacity keeps the weight to a manageable level so that it doesn't have to be emptied as often. (8 lbs per gallon).
542196
Super cute--however, it only holds a gallon. If it held at least 2 gallons it would be much better suited for parties.
567044
It is nice to not carry a heavy two gallon bottle with one arm and spray with another.
Had some difficulty with the hand valve shutting off...  It would stick in the open position and I would have to use my other hand to manually closed the valve.
I disassembled and cleaned it thoroughly and it worked good for a few minutes and then started sticking open again.
I can only guess that there must be some debris remaining in the tank from when it was manufactured as I have only used clear premixed weed killer in the sprayer.
I'll clean it one more time then I will need to return it for replacement.