UpStart Battery 2x Pack - BA300 Replacement Battery for Sennheiser RS 4200, IS 410, Set 830-TV, RR 4200, RI 410, Set 830 S, RI 830 brand with Replacement Battery for Sennheiser BA300, Set 830-TV, RI 830, Set 830 S, RI 830 S, IS 410, RI 410, RS 4200, RR 4200 Battery Capacity: 150mAh, Voltage: 3.7, Type: Lithium Polymer Lifetime Warranty On Sale for a Limited Time! Grade A Quality. High Capacity.