Review on Capetsma Aquarium Filter Sponge Fish Tank Filter Kit - Ultra Quiet Sponge Filter for Aquarium Air Pump, Includes Spare Sponge and Bio Balls by Dianna Kay

Does not absorb water through a sponge so cannot be used as a filter. It's just an air stone with a sponge on the end. Which isn't bad, I was just under the impression that this would actually help with filtering. I like the look of it, but it's not what I was hoping for. It causes superficial excitement, but that's about it. After connecting to the air pump with a hose, the air comes out directly from the pipe connector and exits at the outlet. If it were actually sucking/filtering water from a sponge, water would flow out of the outlet, not just air.