Description: Power: 2.1 interface 8-25V DC power supply Audio Input: stereo input various versions of the bluetooth connection, using CSR8635 Bluetooth chip, bluetooth V4.0, high software compatibility Output Impedance: 8? best(4, 6, 8, 16? impedance can drive speakers) Output Power: Add pre-5532 output foot TDA7492 digital amplifier chip, designed to optimize the circuit layout, the sound quality is very good. Module Size: Approx. 80 x 50 x 20mm / 3.15 x 1.97 x 0.79inch Color: Red Material: Plastic Package Includes: 1 x Wireless Digital Bluetooth CSR4.0 Audio Receiver Amplifier Board