OceanReef Communication Cable Floaters

The OceanReef "Damper" is a sound distortion attenuator
 

GSM MERCURY Underwater Wireless Communication Unit - Mask sold separately 

This unit is blending four different OCEAN REEF units into one: the extended range of the Gpower, the like-stereo sound of the GSM G.power SL, the clearness and double channel option of the DC and the battery life of the Gdivers.

Surface operator can easily change from one channel to the other by pressing a button, distinguishing two different lines of communication if needed.