Panasonic high-temperature long-life Nickel Metal Hydride battery
Amazon.co.jp: Panasonic Original Ni-MH Rechargeable Battery for the Panasonic KX TG2511ET – Panasonic tg2512et & Panasonic KX-TG2513ET And Other DECT 6.0 Digital Cordless Phone Set : Electronics
Amazon.com: Panasonic HHR-75AAA/B-6 Ni-MH Rechargeable Battery for Cordless Phones, 700 mAh (Pack of 6) : Electronics