How to use the 4-channel audio source switching board: 1 to 4 mode (two-channel signal is input from OUT terminal, and output from IN1-IN4 terminal through a switch). 4 chose 1 mode (signals can be input from 4 IN terminals and output from OUT terminals through a switch). The switch is equipped with fixed screws, which is convenient for installation and fixation, without power supply, and no electromagnetic interference. The input and output of the adopts an integrated lotus socket . Switching board pcb size: 90mm x 32mm Color as shown Material: plastic + metal Package Contents: 1 x signal switch board Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.