The HHR-65AAABU is a model number for a rechargeable battery typically used in cordless phones. This battery is commonly found in various models of Panasonic cordless phones. Here are some phone models that commonly use the HHR-65AAABU battery: Panasonic KX-TG Series KX-TG1031, KX-TG1032, KX-TG1033, KX-TG1034 KX-TG8231, KX-TG8232 KX-TG9331, KX-TG9332, KX-TG9333 KX-TG9341, KX-TG9342, KX-TG9343 KX-TG8231, KX-TG8232 KX-TGA101, KX-TGA930, KX-TGA935 Other Compatible Models Some older models of AT&T and cordless phones may also use this type of battery, though Panasonic is the most common brand associated with it. To ensure compatibility, check the specific model number of your phone and compare it with the battery requirements listed in the user manual or the battery compartment.