The product core is the high-end decoding chips ES9023 and ES9038, which have CD level sound quality. They are much ordinary toy level Bluetooth boards in terms of hierarchy, dynamics, details, and high and low frequency extension. They have no burrs at high frequencies, rounded mid tones, powerful low frequencies, and good elasticity The product is designed with one channel of AUX input for easy switching of external wired audio sources. Bluetooth takes priority and automatically switches to AUX state when there is no Bluetooth connection. It is very convenient to switch between AUX and Bluetooth using a silver plated contact high-precision relay, and the signal is non-destructive and sound free The operational amplifier circuit adopts a dual power supply design and is equipped with an operational amplifier base. In the later stage, different operational amplifiers can be replaced to obtain their favorite voices, such as OPA2604, 0PA1612, LM49720, MUSO2, etc Fever version QCC5125 ES9038Q2M Dual lossless -HD LDAC The fever version supports DC 5V to 35V Colour:Photo Color Material:plastic Package Contents: 1 x decoding 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.