Noise Cancelling Wireless Headphones With Mic Foldable Bluetooth Headset and TV PC Tablet Bluetooth Adapter Gaming TV Music Gift Model: B39 with Bluetooth adaptor Uses: wireless headphones, voice headsets. Bluetooth version: V5.0. Bluetooth mode support: A2DP 1.2, AVRCP 1.0, HSP, HSF 1.5. Frequency: 2.402-2.480GHZ, 2.4G ISM band. RF performance: receiver sensitivity: -84dBm; transmit power up to 4dBm. Frequency response: 20 Hz-20 KHz. Signal to noise ratio (SNR): 98Db. Total harmonic distortion rate (THD) 0.1%. Power indicator: Red and blue indicators flash alternately. Headphone charging: rechargeable 400MAH lithium battery. Charging port: USB charging interface. Normal charging time: 2.5 hours. Talk time: up to 10 hours. Standby time: up to 20 days. Working temperature: -20 C -55 C. Other features: support status indicator, charging indicator display. Color: black red,red black,white,black.blue 1 x Bluetooth headset. 1 x Bluetooth adaptor for TV 1 x charging cable. 1 x 3.5mm audio cable. 1 x Chinese and English user manual. 1.Because the packing size and other reasons, the