Review on 🐠 Tetra Whisper Bio-Bag Unassembled Filter Cartridges for Aquariums: Enhance Water Quality Efficiently by Rob Vizitei

I have a TopFin 10 surge protector and these cartridges fit perfectly. Be sure to select a medium size in the Tetra filter. Power cartridges consist of 3 elements: (1) flat plastic holder, (2) bio-pouch and (3) charcoal. As mentioned in other reviews you will need an OEM plastic top fin holder as the holder that comes with the Tetra cartridges will not fit the Top Fin 10 power filter (it is a slightly different shape at the bottom). Just buy a set of two Top Fin cartridges and you'll get the right plastic holder; Use it for as long as possible. The Tetra Medium Bio bag fits easily on the original Top Fin plastic holder. Fill with the included charcoal and voila. Works great. To be honest, when a small 6-pack of Top Fin 10s is $12.99 at Petsmart and a 12-pack of Tetra is $7.48, the decision is easy to make.