UL134 - Ni-MH, 2.4 Volt, 500 mAh, Ultra Hi-Capacity Battery - Replacement Battery for V-Tech 89-1337-00, BT28433 Cordless Phone Battery Replacement Battery for V-Tech 89-1337-00, BT28433 - 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