Sennheiser BA 151 Rechargeable Battery for IR and RF Wireless Headsets Rechargeable accupack suitable for: IS 150, IS 300, Set 810, Set 250, Set 500, IS 380, Set 820, Set 2500, RS 4, RS 6, RS 8, RS 400, RS 30, RS 40, RS 45, RS 60, RS 65, RS 80, RS 85, RS 2400, HDI 302 and A 200. NiMH-rechargeable accupack Voltage: 2,4 V Capacity: 70mAh