For Sennheiser RI900 RR840 RI410 RS4200 RR4200 HDI830
3.7V 150mAh
For Sennheiser Momentum 2 / 3, HD 4.40BT, HD 4.50
3.7V 620mAh
For Sennheiser LSP 500 Pro
14.4V 4.4Ah/63.36Wh