Penn-Plax Bubble Wall is a super-porous, non-clogging aeration product designed to create a dramatic mist of healthful bubbles in any aquarium. It is the only one which can be easily regenerated because you can use a pin or needle to puncture with as many small holes as needed. The tough, Polycyl material not only resists clogging, but will also stand up under repeated reconditioning. Additional Bubble Walls can be joined with the enclosed connector, and can be cut with a razor blade to divide or shorten.