Built-in 6400mAh lithium battery with LCD power display. with broadcast call function. Three-way call function, optional diver call function. Diver intercommunication function. Optional helium-oxygen mixed gas diving ammonia voice recovery function and long-distance communication function. Imported shell, U.S. imported components. Interface. Equipped with dual 2-wire and 4-wire communication cable interface, two-way interoperability with expansion module. Talking handle interface, recording output interface, anti-reverse charging interface, with functional interface for playing music to divers.