General SpecificationsBluetooth version 4.1 Headphone cable length 78.0 centimeters Weight 16.5 grams Audio SpecificationsDriver size 12.5 millimeters Driver sensitivity at 1k Hz/1m W (d B)100d B Impedance 32.0 ohms Control and Connection SpecificationsBluetooth frequency 2.402 G Hz-2.48 G Hz Bluetooth transmitted modulation G F S K, D Q P S K and 8-D P S K Bluetooth transmitter power 0~4 dbm BatteryDynamic frequency response range (Hz)20 Hz - 20 k Hz Battery Type Polymer Li-ion Charging time 2 hours Play time 6 hours Speed Charging time 2 hours Talk time 6 hours FeaturesBuilt-in Microphone Yes Flat Cable Yes Hands Free Call Yes Rechargeable battery Yes