INSMA Amplifier Board 25W+25W Dual Channel Wireless Bluetooth 4.0 Audio Receiver Digital Amplifier Board with 3.5mm Plug(TDA7492P Chip) Amplifier board is small enough to close to a credit card with TDA 7492 chip, Designed to optimize the circuit layout. Bluetooth connection, remember your device, ready to open the door to the music world anytime. The 2x25 W board best fits 8 Ohm and 15W-25W loudspeaker. Fully protected against overvoltage, undervoltage, overcurrent and thermal overloads, etc. TDA 7492P digital amplifier chip, designed to optimize the circuit layout, the sound quality is very good ,big power. DIP switches can be more easily directly adjusted after-class amplifier gain,to better promote the impedance larger speakers.