Radio Shack 23-964 Cordless Phone Battery Ni-CD, 3.6 Volt, 600 mAh - Ultra Hi-Capacity - Replacement for Panasonic HHR-P505, UNIDEN BT990 Rechargeable Battery Replacement Battery for Panasonic HHR-P505, UNIDEN BT990 - Ni-CD, 3.6 Volt, 600 mAh. Compatible with your OEM battery. Made with high quality cells.