The product has a beautiful appearance, exclusive private mold, including design patents Designed with Bluetooth 5.1 chip for greater compatibility and stability Bluetooth receiver (RX) and Bluetooth transmitter (TX) in one High-definition LED digital display for clear visibility of working status and Bluetooth mode Built-in DSP decoder chip, heavy bass effect, the device supports treble/bass button adjustment Upgraded NFC function, mobile phone induction is connected at a touch Controllable indicator light, soft and non-blinding, the light brightness follows the volume level to brighten/darken accordingly Built-in 1200mAh rechargeable lithium battery, long battery life Support U disk/TF card playback and transmit, support MP3/WMA/SBC/WAV/DTS/A52/FLAC/AAC/AIF/AMR/APE format Built-in FM radio, one key to search and save stations automatically, the frequency can be adjusted from 87.5~108 Support 5-8m red private mode external cable remote control, mode/signal/volume/up/down track/mix/microphone, and various other operations Built-in 6.5mm HD microphone, support microphone access for singing, built-in anti-whistle design Easy to connect, no driver or APP downloading Specifications: Product Model: M9 Bluetooth Version: Bluetooth V5.1 Protocol Support: A2DP/AVRCP/HSP/OPP/GATT/SM Operating band: 2.402GHz - 2.480GHz Power Level: Power Level 2 (Class II) Sensitivity: -85dBm <0.1% BER SNR: ≥90dB Distortion: ≤0.1% Input Connector: 3.5mm AUX+RCA+FM+USB+TF Connector+6.5 MIC  Output interface: 3.5mm AUX+RCA Receiving Parameters: FM 87.5-108MHz Supported formats: MP3/WAV/WMA/APE/FLAC/G729/M4A/ALAC/AMR/DTS/MIDI/G726/MTY Screen size: 36*8MM Operating current: <40mA Built-in battery: 3.7V/1200mAh Charging current: approx. 1000mA (MAX) Charging time: approx. 1.5 hours Endurance time: RX approx. 8H, TX approx. 8H Bluetooth distance: ≤ 30M (barrier-free) Charging method: Type-C 5V/1A Compatible devices: Android, IOS mobile phones and tablets, active speakers, amplifiers, and Bluetooth speakers or headphones that support A2DP/protocol connection Use