Cameron sino 700mAh Ni-MH Replacement BP-HP550-11 Headset Battery For Sony MDR-RF860 MDR-RF4000 MDR-RF970 MDR-RF970RK MDR-RF925 MDR-RF925RK MDR-RF4000K MDR-RF860RK MDR-RF850 MDR-RF810 12 Months Warranty Replacement for the Following Battery Model/Part Numbers:BP-HP550-11 Compatible with the Following Models:Sony MDR-RF860, MDR-RF4000, MDR-RF970, MDR-RF970RK, MDR-RF925, MDR-RF925RK, MDR-RF4000K, MDR-RF860RK, MDR-RF850, MDR-RF850RK, MDR-RF840, MDR-RF840RK, MDR-RF810, MDR-RF810RK,MDR-IF245RK Capacity: 700mAh/1.7Wh 2.4V Ni-MH Rechargeable Battery Pack. Cameron Sino Over 10 Years Battery Manufacturing Experience