Sony MDR-RF925RK Battery - Replacement for Sony BP-HP550-11 Headphone Battery (700mAh, 2.4V, NI-MH) Compatible with Sony BP-HP550-11, MDR-840, MDR-850RK, MDR-925, MDR-970RK, MDR-RF810, MDR-840RJ, MDR-860, MDR-925RK, MDR-RF4000, MDR-810K, MDR-850, MDR-860RK, MDR-970, MDR-4000RK, MDR-RF4000K, MDR-RF810RK, MDR-RF840, MDR-RF840RK, MDR-RF850, MDR-RF850RK, MDR-RF860, MDR-RF860RK, MDR-RF925, MDR-RF925RK, MDR-RF970, MDR-RF970RK Battery Capacity: 700mAh, Voltage: 2.4, Type: Nickel-Metal Hydride Lifetime Warranty On Sale for a Limited Time! Grade A Quality. High Capacity.