Attaches directly to work safety helmets, cordless and safe small walkie talkies. Supports alternating calls and alternating calls / Simultaneous calls 47ch Specific Small Power Transceiver Certified Model IP67 Dust Resistant Equivalent (Only main unit and mic not included) By attaching directly to the helmet, you eliminate the hassle of earbud microphone cables and the danger possible by hooking the cables.Supports alternating calls and two parties simultaneous calls as well as intermediate calls.The dip switch, color LED and voice guidance are used to set up, so even without an LCD screen.In addition, it uses both our exclusive ACSH (Ashshe/Auto Connect Shake Hands) that recognizes and automatically set the current channel and group talk numbers, and an air drone that copies the parent console settings to any number of sets mode items wirelessly.