GP GP80AAAH3BXZ Cordless Phone Battery Ni-MH, 3.6 Volt, 800 mAh - Ultra Hi-Capacity - Replacement for Clarity C4220/4230 Rechargeable Battery Synergy Digital Replacement Battery for Clarity C4220/4230 Ni-MH, 3.6 Volt, 800 mAh. Made with high quality Japanese cells. 100% compatible with your OEM battery - 3 year warranty. Synergy Digital is a Registered Trademark