Sennheiser's BA 10 is an evolution wireless SKM D1 or AVX Handheld Transmitter rechargeable battery pack (sold separately). It can be utilised to swap out the transmitter unit's two AA-sized batteries. A lithium-ion 3.7V rechargeable battery powers the BA 10.
Compatibility
Sennheiser AVX 835 SET
Sennheiser AVX Combo SET
Sennheiser AVX SKM AVX
Sennheiser AVX...