1、Amplifier Board: Supporting audio input from AUX and 5.0 bluetooth, has higher transmission efficiency and longer transmission distance. 2、Beautiful Sound: 2.1 sound channel enables a maximum output power, 2x50W+100W, and the antenna with base also ensure stable signal. 3、Secure Working: Has all round protection against short circuit, over current, overheating as well as anti reverse protection to prevent failure. 4、Easier Control: Allows for convenient control on bass, treble, subwoofer frequency and volume, so you can freely enjoy the music you want. 5、Wide Application: Through quick and easy connection, the amplifier board is widely compatible with home theatre, large speaker and so on. Item Type: Amplifier Board Material: Printed Circuit Board Function: Power Amplifier Board Model: ZK-TB21 Chip: TPA3116D2 Bluetooth Version: 5.0 (unobstructed, approx. 10m / 32.8ft) Audio Input: AUX + Bluetooth Number of Channels: 2.1 channels. Input Sensitivity: 500mV Speaker: 20-100W, 4-8Ω Output Power: Maximum 50W (left and right channel), maximum 100W (subwoofer). Protection Mechanism: Overvoltage protection, undervoltage protection, overheating protection, DC detection, short circuit protection. 1 x Amplifier Board 1 x Wire Input Socket 1 x Screwdriver