VOX(Voice Activation) Separate Front Inputs for Music & Smart Phone Audio Output 2 Front Headphone inputs (Front of Unit) 2 Rear Headphone inputs (Back of Unit) RF Shield Housing High Output NB200 Behind The Head Style Headset Noise cancelling Smart Mic ò High fidelity bass enhanced speakers (Stereo) Flexible Position Mic for VOX (Voice Activation) Easy to use Large Volume Control Knob Carbon Fiber Finish Deluxe Ear pads Compatible with HCF4, HCR16 and HEC10 to extend (cable sold separately) Comfortable Ear pad. INTERCOM W/HEADSET