Audio Technica ATH M50X BT2

Headphones :
TypeClosed-back : dynamic
Driver Diameter : 45 mm
Sensitivity : 99 dB
Frequency Response : 15 - 28,000Hz
Impedance : 38 ohms

Microphone : 
Polar Pattern : Omnidirectional
Type : Condenser
Sensitivity : -38 dB (1V/Pa at 1kHz)
Frequency Response : 85 - 15,000Hz

General : 
Battery Life : Approx 50 hours continuous use
Battery Info : Required, includedBattery MaterialLithium Polymer
Battery Quantity : 1year 
Battery Type-Weight : 10.82 oz (307g) (Without Cable and Connector)

Bluetooth Version : Bluetooth Ver.5.0
Operating Range : Line of sight - approx. 33' (10m)
Battery : DC 3.7V lithium polymer battery
Charging Time : 3,5h