Expresscomm PoC Walkie Talkie 2 Wire Surveillance Kit Earpiece MC400 LTE Advanced Pro Modem (1200 Mbps) The level dependent digital audio circuit MOCS II Wireless SpeakerMic for for use with KA Helmet kits includes cell phone button (Type of Portable Radio):Motorola APX The level dependent digital audio circuit automatically detects harmful noise levels and compresses them to safe decibel levels Environmental microphones for level dependent hearing protection and ambient listening One wire has a combined push to talk button and microphone Plug the K Type 2 Pin connector into the audio port on the side of your Expresscomm device