HQRP Battery for Sennheiser RR840 / RR 840, RR840-S/RR 840 S, RS4200 / RS 4200, RI830 / RI 830, RI830-S/RI 830 S, RI900 / RI 900, RR4200 Headphones/Receiver plus Coaster HQRP&reg; Rechargeable Battery plus HQRP&reg; Coaster; Battery Voltage: 3.6V; Capacity: 140 mAh; Li-Pol; Compatible with Original Battery; 200 Days warranty! Compatible with: Sennheiser RR840 / RR 840, RR840-S / RR 840 S, RS4200 / RS 4200, Sennheiser Set840-S / Set 840 S, Set840-TV / Set 840 TV, Set900 / Set 900, Sennheiser RI830 / RI 830, RI830-S / RI 830 S, RI900 / RI 900, RR4200 / RR 4200, Set830 / Set 830, Set830-S / Set 830 S, Set830-TV / Set 830 TV Headphones Receiver