Features: Built-in 400mAh rechargeable lithium battery, long life; support USB (U disk), TF card for play and transmission. brand new and high quality Built-in digital to analog chip, support AUX, RCA, USB, TF interface. Built-in high-definition microphone, support wireless listening to songs, hands-free calling etc . Equipped with a high-definition LED digital display, the working status and Bluetooth-compatible mode are clearly visible. The appearance of the product is exquisite, and the Bluetooth-compatible receiving (RX) and Bluetooth-compatible transmitting (TX) two-in-one Using Bluetooth-compatible 5.0 chip, compatibility and stability are for stronger. Specifications: Bluetooth-compatible version: V5.0 Supported protocols: RX: A2DP AVRC TX: A2DP Working frequency band: 2.402GHz -2.480GHz Power class: Class 2 (Class II) Signal to noise ratio: approx 90dB Distortion: less than 0.1% Input: 3.5mm AUX+RCA+USB+TF Output: 3.5mm AUX+RCA Supported formats: MP3/G729/M4A/ALAC/DTS/MIDI/G726 Working current: less than 40mA Built-in battery: 3.7V/400mAh Charging current: about 500mA Charging time: about 1 hour Life of Battery : RX about 6-8H, TX about 8H Bluetooth-compatible distance: approx 10M/3.3ft Charging method: Micro USB 5V/0.5A Compatible devices: Android, IOS system mobile phones and PADs, active speakers, and Bluetooth-compatible speakers or headphones that support A2DP/protocol connection Product size: approx 70x70x30mm/2.75x2.72x1.18in Package Includes: 1pc X Bluetooth-compatoble Adapter Host 1pc X Type-c Charging Cable 1pc X 3.5mm Audio Cable 1pc X Red And White RCA Cable 1pc X Manual note: There might be a bit color distortions due to different computer resolutions. There might be size errors due to different computer resolutions.