A helmet-mounted PRR-9 receiver worked in conjunction with a PRT-4 hand-held walkie-talkie transmitter. This system was used primarily at the squad and platoon level. (Martin Brayle/Dreamstime)
Martin Brayle/Dreamstime
Vietnam helmet radio
A helmet-mounted PRR-9 receiver worked in conjunction with a PRT-4 hand-held walkie-talkie transmitter. This system was used primarily at the squad and platoon level. (Martin Brayle/Dreamstime)
Martin Brayle/Dreamstime