Kastar Replacement Battery for Sony MDR-RF4000K MDR-RF4000 BP-HP550-11 Headphone

Compatible with the following Sony battery models: Sony BP-HP550-1 BPHP5501 Sony BP-HP550-11 BPHP55011 Compatible with the following Sony headphone models: Sony MDR-IF245RK MDRIF245RK Sony MDR-RF4000 MDRRF4000 Sony MDR-RF4000K MDRRF4000K Sony...