The Electro-Voice RE3-BPTRSB-5L is a compact, lightweight UHF bodypack transmitter specifically modified to work exclusively with the RSB-2 Referee Switch Box. Designed for sports officiating, it features a robust all-metal housing that is easy to wear and conceal while providing durability for demanding use. The transmitter uses ultrasonic sync to transfer frequency and functional settings from the receiver for quick and easy setup. Selectable RF output power of 10 or 50 mW helps accommodate different transmission range requirements. Its unique magnetic sliding latch and locking mechanism provide secure battery access, while the built-in charging contacts support the optional BC2 charging station for compatible NiMH rechargeable batteries. Operating in the 488–524 MHz frequency band, the RE3-BPTRSB-5L offers a 36 MHz tuning bandwidth and operates on two AA alkaline or rechargeable NiMH batteries. It features a 4-pin mini input jack for connection to the RSB-2 Referee Switch Box.