The Sony 988521843 rechargeable battery is a replacement power source for compatible Sony headphone equipment. It is identified as a nickel-metal-hydride battery, also designated BPHP800 and reference M3437.
Its 2.4 V rating and 800 mAh capacity describe the battery’s electrical output and charge capacity. The rechargeable design allows it to be charged again for continued use in supported equipment.
The listed compatible models are Sony MDR-RF895R, MDR-RF895RK and TMR-RF895R. This part is intended for headphone equipment using this battery reference.