Fluval 106/206 & 107/207 Bio-Foam+. Designed specifically for Fluval 106/107, 206/207 canister filters, Bio-Foam+ performs double duty as both an effective mechanical and biological media. Key Features : Mechanical/Biological filter media Large porous surface area supports expansive beneficial (nitrifying) bacteria growth Effectively captures small particles and debris, particularly those that are not retained by the first stage of foam filtration Custom fit for FX Series filters to increase filtration efficiency Helps create a healthy aquarium and ideal water conditions Rinse every 3 months Replace every 6 months For fresh and salt water use Single Pack.