Works when connected to a 12 volt DC source, Needs a new battery pack, rebuild this one with rechargeable NiCads, Or use your vehicle as a base station. Monitor Heavy traffic while driving off-road. Communicate with main office when driving on private logging roads. Manual and instructions can be found online. Relm WHS 150 VHF Radio. Up to 16 channels can be installed, 148 to 174 MHz. A VHF radio shop will be able to program the frequencies you need. Comes with the extended antenna for max distance, maybe 30 km or more. Has a belt clip, comes with the original Relm charger.