The Tetra Whisper Internal Power Filter mounts on the inside of an aquarium or terrarium instead of hanging off the back, allowing the tank to sit flush against a wall. Because the motor runs fully submerged, operation is notably quiet compared with hang-on-back designs. The unit can function in as little as two inches of water, making it suited to turtle tanks, amphibian setups or shallow-water displays in addition to standard fish aquariums. Filtration happens in three stages: a dual-sided mesh cartridge traps debris and waste, activated carbon inside the cartridge reduces odor and discoloration, and a biological scrubber component supports beneficial bacteria growth. Each unit ships with one pre-assembled Bio-Bag filter cartridge already in place. Mounting is done with suction cups or an included clip, letting the filter adjust to different water levels. The housing is submersible plastic construction designed to plug into a standard household outlet.