Replacement battery for Bluetooth-Headphones Earmuff. Specifications: 1100mAh, 3.7V, Li-Polymer. Compatible with: Bluetooth-Headphones Earmuff, Ear Defenders, Male Jack AM/FM Radio bluetooth Headphones. Replaces: PROTEAR AB/S1 (Black Version). PROTEAR replacement battery designed for Headset devices. A precise, secure fit you can rely on.