HAVIT i62 90° Rotation Ear-Muff Wireless Headphone. Bluetooth Version: V5.1. Product size: L199 * W50 * H176 mm. Net weight: 200g. Wireless working range: 10M (without obstacles). Speaker: F40mm. Speaker frequency: 20-20khz. Speaker sensitivity: 103±3db at 1khz,1mw. Impedance: 32O±15%. Battery: 400mAh. Playing time: Up to 8H. Talking time: About 2.5H.