HBQ I7S Double Dual Mini Wireless 4.1 Bluetooth Earphone With Power Case - White HBQ I7S Double Dual Mini Wireless 4.1 Bluetooth Earphone With Power Case - WhiteHBQ I7S Double Dual Mini Wireless 4.1 Bluetooth Earphone With Power Case - WhiteDrive: 15mmImpedance: 32 OHMBluetooth version: Bluetooth v4.1+EDRBluetooth frequency: 2.4GHzPower level: CLASS II, output power: 30mWBluetooth Distance: obstacle-free 10 metersFrequency response: 20-20000HzWorking voltage range: 3.0V-4.2V