SENNHEISER BA30 BATTERY FOR AVX SERIEN

Sennheiser BA 30

The BA 30 from Sennheiser is a rechargeable battery pack for the evolution wireless SK D1 or AVX Bodypack Transmitter (sold separately).
It can be used to replace the two AA size batteries that power the transmitter-unit. The BA 30 uses a lithium-ion 3.7V rechargeable battery.