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

They work great!

Took less than a minute to put a cartridge together. Its definitely worth saving money and doing it yourself.

GREAT FILTERS!

This is an easy option for bulk filters.

Very good product

Worked as expected

Very happy with this item. Great for your money.

These ones fit the filter I have on my fish tank, so thats all that matters. Therere fine granules of carbon inside the pouch thing, which filter the water. Only thing is: you have to put the carbon in yourself; it comes in little pre-measured packets. PIECE OCAKE. The ones I used to use have gotten fancier; they now come already pre-assembled, but in pet stores, they are PRICY! These ones cost considerably less but are exactly the same in every way except you have to put the little carbon granules in yourself, and you keep re-using the little plastic form that goes inside the filter, which is much better because theres much less waste -- an added bonus!

Cost affordable. Cost affordable. Cost affordable. Did I mention it’s cost affordable? A whole years worth for less than what 3 months worth would cost me, if I were to buy these assembled (from walmart).

Very good deal