Rayovac RAY77 Cordless Phone Battery 2.4 Volt, Ni-CD 700 mAh - Replacement For SONY BP-T50 Replacement Battery for Sony BP-T50 - Ni-CD, 2.4 Volt, 700 mAh. 100% compatible with your OEM battery - 3 year warranty. Made with high quality Japanese cells. Synergy Digital is a Registered Trademark