This product is a stereo digital audio channel switcher with volume, treble, and bass adjustment functions, EQ, custom sound effects, noise isolation, and infrared remote control for one-touch switching. Bass Control: 28 levels/2 dB, -14 to +14 Treble Control: 28 levels/2 dB, -14 to +14 Input Gain: 3.75 dB to 11.25 dB Maximum Input Signal: 1.2 Vrms Channel Separation, f=1 kHz Total Harmonic Distortion (THD): 0.01-0.1% Functional Description: 1. Mute: Press the encoder twice in succession. In mute mode, rotate the encoder left or right to unmute, or press the encoder twice in succession. 2. Volume: Rotate the encoder left or right to decrease the volume on the left and increase the volume on the right. 3. Treble: Short press the encoder to illuminate the "H" LED, indicating the treble setting. Rotate the encoder left or right to change the parameter, also enabling custom sound effects. If the encoder is not pressed within 5 seconds, it automatically switches to volume up or down. 4. Bass: Short press the encoder to illuminate the "L" LED, indicating the bass setting. Rotate the encoder left or right to change the parameter, also enabling custom sound effects. If the encoder is not pressed within 5 seconds, it automatically switches to volume up or down. 5. Channel Switching: Press and hold the encoder for 2 seconds to switch between CH1 and CH4. 6. EQ Sound Effect: Press the EQ button on the remote control. 7. Power Supply: DC 5V, stable operation with less than 100 mA. Power sources include USB ports on devices, computers, mobile phone chargers, and other devices with USB ports. Operating Voltage: DC 5V, 100 mA Volume Control: 63 levels/1.25 dB Color:Black Material:Aluminum Alloy Package Contents: 1 * Audio Switcher 1 * Remote Control