Panasonic madeHHR-P303. Or Battery Barn madeBAT-303. Works for Panasonic ,AT&T , Cobra, SONY , GE and many many different brands' phones. HHR-P303--- The newer Ni-Mh battery to replace the old Ni-Cad P-P303 battery, 3.6 V , 350 mah. Dimensions at 1&11/16" L x 1&1/8" W x 9/16" H. The battery is made by Panasonic. In Panasonic sealed brand new package. You will have one year's warranty from Battery Barn. Priced at $7.25 . We also have Battery Barn made same battery, BAT-303 ($4/95), please see below for the details.