ChatterBox CB-50 Tandem Pro Communicator Kit - -- The HJC-50 Tandem Pro takes all the benefits of the highly rated HJC-40 and adds much, much more. Some of these features include:True Stereo SoundRechargeable Ni-MH batteryHome chargerSpecial input for certain cell phonesWith little more than a whisper the Tandem 50 will send your words streaming through the mic and into the earphones of your passenger in full stereo sound. The tandem 50 is a full duplex intercom system so you will always be in constant two-way communication