The AQUAEL filter sponge cartridge is designed for the Hypermax external filter, offering precise punching for a perfect fit. It provides both mechanical and biological cleaning benefits for aquarium water. Specifically designed to complement the Aquael Hypermax external filter, this filter cartridge ensures optimal performance. The standard filter sponge, featuring a 20 PPI pore size, is located in the lower section of the external filter, serving coarse filtration purposes.