Tetra Whisper Bio-Bag Filter Cartridges For Aquariums - Unassembled Medium (Pack of 12)

Work as expected. Great value

I love these more than the pre made version. Very easy to assemble. Keep the tank clear ! great value.

Easy to fill, and great prices.

Easy to assemble and keeps the tank water crystal clear.

Works on my fish tank

If you will assemble these (super easy) you will save a ton of money

I like these (with the tablet) better than just using the activated charcoal. The tablet keeps the water much more clear

Sure beats me having to run to the store to buy these. The only thing I will use for my fountains and my goldfish.

Not that great

Perfect fit for whisper replacements however be aware that they provide only 1 new frame! So you have to get your hands a bit dirty in replacement!