The UIIraLITE Dual Headsets allow users to remain in constant full-duplex voice contact even while on the move. What sets them apart from most other wireless headphones is that they work without belt transceivers. All electronics, including the battery, are installed right inside the headphones. The UltraLITE Double includes deluxe padding and a fully adjustable noise-canceling microphone to ensure effective voice communication even in high-noise environments. Rechargeable lithium battery Since the UItraLITE headphones have self-contained. "All-in-one" design of all electronic components, including the battery, is installed in the plastics of the headphones. The batteries are lightweight and about the size of a match book. They charge in about 3 hours, run for 6 hours and can be changed in seconds. Since they are lithium-ion, the batteries do not have to be drained after each use and will never develop a memory