When communicating underwater at close range or in closed environments, it is often possible that audio distortion is caused by excessive transmission strength. Transmitters are relatively powerful, and if they are used in a pool or very close together, distortion can be created. The sound is then "out of tune" and becomes difficult to understand.

The "damper" can be inserted on the antenna; it is made of a spongy material with many small air pockets. The combination of the two materials creates the necessary filter to reduce the transmission power as needed and make the conversation intelligible again.