AT&T-Lucent BT5633 Cordless Phone Battery Ni-MH, 3.6 Volt, 750 mAh - Ultra Hi-Capacity - Replacement for AT&T-Lucent 27910 Rechargeable Battery Replacement Battery for AT&T-Lucent 27910 - Ni-MH, 3.6 Volt, 750 mAh. 100% compatible with your OEM battery - 3 year warranty. Made with high quality Japanese cells. Synergy Digital is a Registered Trademark