Please Note: This Version Only has Communication Function, No Noise Reduction Function // This Product Cannot be Used Alone and Needs To be Used with PTT. New Design Ear Cup Provide Clear Voice and Comfortable Support. No need to install battery, battery Slot and Buttons is For Decoration (Useless). Use Headset by Hang On the Helmet // Detachable microphone Free to Install // fits 19~21mm helmet side rail. Multi-Usage: Expansion Activities, Tactical Games, Film and Television Props, Team Activities, Cosplay and Other Outdoor Sports.