Omama Rectangular Fish Tank Biochemical Filter Bio Sponge Pad, 2-Piece, Black
Brand: Omama

You can cut the size as you need.
Can be used again after cleaning.
Package content : 2 x biochemical filter sponge

Filter function to decomposing the excrement and forage leftover.
Please wash it once per month to avoid its blocking and deforming.
It can be cut as your need, promotes nitrogen cycle, helps reduce the death rate of fish.
Short: 31. 5 x 12 x 2. 5cm/ 12. 4" x 4. 7" x 1" (L*W*T)
Package content : 1 x Coarse Pore biochemical filter sponge,1 x Small Pore biochemical filter sponge