Double Headset UIIraLITE Double headsets allow users to remain in constant full duplex voice contact even while on the move. What sets them apart from most other wireless headsets is that they operate without belt pack transceivers. All electronics, even the battery, are installed right inside the ear cups. The UltraLITE Double includes deluxe padding and fully adjustable noise cancelling microphone to insure effective voice communication even in high noise environments. Rechargeable Lithium Battery Since UItraLITE headsets feature self-contained. "All in One" design all electronics, even the battery, is installed in the headset plastics. The batteries are lightweight and about the size of a book of matches. They charge in about 3 hours, run for 6 hours and can be changed out in seconds. Since they are Lithium-ion, the batteries do not have to be drained after each use and will never develop a memory