Feature: 1. 2 Control Ports: The PCB board reserves 2 control ports, one is to output high level first, and then output low level when power on or pause. The other one is to output a low level first, and then output a high level when it is turned on or suspended. 2. Stable Transmission: The power amplifier board uses Bluetooth 5.0 main control chip, which has good transmission effect and high stability. This is for professional users to use external power amplifier DIY, ordinary users do not need to use it. 3. Button Control: With button control, it can control up and down songs, volume addition and subtraction, play, pause, switch on and off, etc., and reserve high and low level control interfaces, regardless of daily use or DIY modification, with strong playability. 4. Interface Design: Output interface: 3.5mm stereo (reserved welding point, you can DIY by yourself), power interface: micro 5p (reserved 2.5mm welding port, does not support battery power supply) Input voltage: 3.7V‑5V. 5. Multipurpose: The Bluetooth signal of phone, laptop, and tablet can be transmitted to power amplifier, active speaker and other device. The interface can also be connected to 3.5mm headphones to turn into Bluetooth headphones. (without mic, voice chat is not supported). Specification: Item Type: Bluetooth Receiver Board Material: PCB Color: White Bluetooth Version: V5.0 Transmission Distance: About 10 Meters (the Shorter the Distance, the Better the Stability) Output Interface: 3.5mm Stereo (Reserved Solder Joints, You Can DIY by Yourself) Power Interface: Micro 5p (Reserved 2.5mm Welding Port, Does Not Support Battery Power) Input Voltage: 3.7V-5V Signal to noise Ratio: 90dB Total Harmonic Distortion +Noise:-70dB Crosstalk: -86dB DNR: 91dB Transmission Protocol: A2DP/AVCTP/AVDTP/HFP. Package List: 1 x Bluetooth Receiver Module