Headphones incorporating microphones; wireless earphones; wireless communication devices for voice, data or image transmission; wireless headsets for use with mobile phones; wireless communication devices for voice, data or image transmission when applied to protective helmets; headsets with two-way wireless communication function for use when applied to protective helmets; wireless communication headsets for use with protective helmets; two-way wireless communication systems composed of microphones for use when applied to protective helmets;; headsets with two-way wireless communication function;; wireless headsets applied to motorcycle helmets; wireless communication devices for voice, data or image transmission when applied to motorcycle helmets; headsets with two-way wireless communication function applied to motorcycle helmets; two-way wireless communication systems applied to motorcycle helmets; headphones for walkie-talkie; headsets for communications; headsets; headphones; headphone-microphone combinations