The -BT31 16 Bluetooth digital amplifier board, Qualcomm QCC3034 Bluetooth solution version 5.0, supports the -HD//-LL/AAC/ protocol. The power amplifier board supports Bluetooth mode and one channel AUX input mode, automatically switching Bluetooth priority. The maximum output power of the power amplifier is 50W, with one channel and two channels=50W+50W. Colour:As Shown Material:plastic style:B with Antenna 1. Power supply precautions: When the output power of the power amplifier reaches 50W+50W, the power supply must 24V must be 120W, that is, 24V must be 5A. A 12V power amplifier can also work, but the output power is relatively much smaller. When using, match the appropriate power supply according to the power demand. 2. Precautions for horn wiring: The motherboard is marked with interface definition and polarity instructions, and the+sign represents the positive terminal The positive pole of the speaker or passive speaker is connected to the negative pole of the speaker or passive speaker. Never reverse the positive and negative polarity, as it affect the phase of the speaker and seriously affect the sound quality and listening experience. Reminder: When using a bare board without obstruction, an external antenna can be omitted, and the reception distance can reach 10-20 meters. When installing a metal chassis, an external antenna must be added, otherwise the chassis severely block the signal and cause a short reception distance, which may only be 1-3 meters. After adding an external antenna, the distance can reach 10-20 meters. Plastic or wooden casing installation can require or do not require an external antenna. Choose whether to include an external antenna kit based on your own conditions. Package Contents: 1 * power amplifier board 1 set * accessories Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.