High Fidelity Stereo Sound for Smart Phone or other Music Source VOX (Voice Activation) Separate Front Inputs for Music & SmartPhone Audio Output 2 Front Headphone Inputs (Front of Unit) 2 Rear Headphone Inputs (Back of Unit) RF Shield Housing High level output for headphones for sound quality Dimension: 1.6ö H x 4.5ö W x 4.3ö D NH100 Off-Road helmet headphones Noise Cancelling Smart Mic High Fidelity Bass Enhanced Speakers (Stereo) Flexible Position Mic for VOX (Voice Activation) Compatible with HCF4, HCR16 and HEC10 to extend (Cables sold Separately). INTERCOM W/IN HELMET