Cordless phone batteries Model:5/4AAAA2.4V 500mAh Replacement Battery for vTech 89-1337-00-00, BT18443, BT28443 - Ni-MH, 2.4 Volt, 500 mAh. 100% compatible with your OEM battery - 3 year warranty. Made with high quality Japanese cells. Synergy Digital is a Registered Trademark