Main Features of Headphones:- One-click key to answer calls when listening to music or playing games, Using stainless steel and plastic on the reinforced connecting rods, making the headphone strong and durable, Even when the headphone battery runs out, the music can continue to play with the help of the 3.5mm AUX audio plug (not included) , Bluetooth 5.3 supports 10 meters stable connection, High-speed and stable transmission , Portable because the headphone is lightweight and has a foldable design , The headphone features noise cancellation, which allows the headphone to recognize voices through precise voice pickup technology and filter out background noise interference, providing you and the caller with a clear call effect, 40mm high-definition moving coil sounds, creating vivid stage sound and 3D stereo sound with heavy bass Specifications: Model: BL51 Bluetooth version: V5.3 Connection distance: 10 meters Speaker size: 40mm steel magnetic speaker Battery capacity: 400mAh Ampere Charging Time: 2.5 - 3 hours Charging Port: Type - C Talk/Music Time: 8 hours Standby Time: 300 hours Audio Output: Wireless/Wired Impedance: 32 ohms Sensitivity: 75 dB Frequency Response: 20Hz ~ 20kHz Frequency Range: 2.40GHz ~ 2.480GHz Package Contents: 1 x BL51 Headphone, 1 x Type-C Charging Cable