Fangrui Product Details 100w*2+200w 2.1-channel Bluetooth Digital Amplifier, Dual-core Tpa3221. Add Power Switch, ; Lossless Components, Better Sound Quality; Tuning Of High And Low Frequencies, More Convenient. Quality First, Exquisite Materials. Dual Core Is More Stable, Using 2 For Original- Tpa3221 Amplifier Chips. Tpa3221 Chip Audio Power Core, High Efficiency, Low Power Consumption, High-definition Sound Quality And Comprehensive Protection Mechanism. Xy-st21pro Bluetooth Antenna Interface, The First Generation Interface Has Been Welded, And An External Bluetooth Antenna Can Be Connected. Note:self-assembly Is Required. Type:a:bare Board Colour:black Material:plastic Package Contents: 1 * Digital Audio Power Amplifier Board 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.