The BA 20 from Sennheiser is a rechargeable battery pack for the evolution wireless EKP AVX Receiver (sold separately). It can be used to replace the two AA size batteries that power the transmitter-unit. The BA 20 is a lithium-ion 3.7V rechargeable battery.
Compatible with: EKP-AVX, AVX-Combo-SET, AVX-835-SET, AVX-ME2-SET, AVX-MKE2-SET
