The Entel #CMP750 is a submersible, very rugged, heavy duty lapel speaker microphone for the HT series hand portable radio. It is attached with a revolving clip and allows the radio user to carry the radio on their belt and have the facility to both make and receive calls without removing their radio. This keeps the radio safe and ensures that calls are not missed, especially in noisy environments. The CMP750 has a socket (3.5mm mono) to allow an optional earpiece (EHP9) for discreet reception of calls. Note: When the earpiece is attached, the speaker microphone is no longer submersible until the earpiece is removed and the waterproof cover is replaced and tightened.