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.

PRODUCT HIGHLIGHTS :

• For SK D1 or AVX Bodypack Transmitter
• Replaces Two AA Batteries
• Lithium-Ion Rechargeable Battery