smavco Bundle BP-HP550-11 Battery for Sony MDR-RF860 Wireless Headphones Plus Stereo Audio Cable, 700mAh Capacity: 700mAh/1.7Wh Dimension: 46.00 x 23.00 x 11.00mm Compatible Part no's: BP-HP550-11 Compatible Models: Sony MDR-IF245RK, MDR-RF4000, MDR-RF4000K (Refer Description for complete list)