Battery Type: Li-ion Polymer battery Capacity: 1000mAh Nominal Voltage: 3.7V Pack Dimension: 6.0 x 30.0 x 50.0mm Weight: 15g Working Temperature: Less than 60℃(140℉) Compatible Models: AKG Y50BT C50BT Headphone Cautions: 1. DO NOT ATTEMPT OPEN, DISASSEMBLE THE BATTERY. 2. DO NOT CRUSH, PUNCTURE OR DISPOSE OF IN FIRE OR WATER. 3. DO NOT EXPOSE TO ABOVE 60℃(140℉).