Feature: The first Bluetooth audio receiver with an OLED screen has come. You can have all the information of the wireless streaming status from a simple glance at the screen. It shows Bluetooth connection status, battery, volume, and caller’s ID, etc.  We tries the best to offer the best hands-free calling experience by using dual noise-canceling technology. The audio receiver has DSP and CVC8.0 noise-canceling software installed, ensuring both clear listening and authentic voice transmitted.  12 hours playtime is stored in the pocket-sized audio receiver for continuously wireless music streaming. We also guarantees the safety of using the Bluetooth adapter while charging by installing a high efficient lithium battery.  Wirelessly stream your favorite tunes with fast and stable Bluetooth 5.0 technology. The easy and smooth pairing with different devices is uninterrupted within a range of up to 40 feet, allowing free and seamless audio enjoyment.  Bluetooth music receiver provides Hi-fi wireless audio experience with a built-in chip that supports AVRCP, A2DP, HFP, and HSP profile. If you prefer rich bass and stereo sound, just press “+” and “-“ buttons to activate surround sound effects.     Specification:  Model No: B31 OLED Bluetoo 5.0 Receiver;  Bluetooth version: Bluetoo V5.0;  Support protocol: A2DP, AVRCP, HFP, HSP;  Working frequency: 2.402GHz -2.480GHz;  Power rating: Class II;  Receiving sensitivity: -90dB at 0.1% BER;  Working current: ＜30MA (screen off);  Built-in battery: 250MAH;  Charging current: about 200MA;  Charging time: about 2 hours;  Display content: Bluetooth connection status, playback status, volume value, power value, device name, music spectrum;  Life time: >10H;  Bluetooth distance: >10M (open place);  Charging method: Micro USB 5V;  Output connection mode: 3.5MM stereo interface;  Compatible: Android, IOS system mobile phone and PAD, and other audio equipment with AUX input function;     Package Included: 1 x Bluetooth 5.0 Receiver Adapter;  1 x Micro USB Power Cable;  1 x 3.5mm AUX Audio Cable;  1 x User Manual