Board size: 7.9x4.5CM, Fixing hole distance: 7.4x4CM QCC5125 supports /AAC//APTXLL/APTXHD/AD/LDAC AUX audio input, low power consumption, power on, maximum default volume, 2x4/8 ohms 10W/15W, supports external first generation antenna, knob switch and volume 7-15V power supply (at 12V3A, the maximum output power is 2x15W) VCC, GND: power supply pin, with reverse connection protection Key Description: "KCOM": key common terminal "VOL+": Short to increase the volume, long to continue the volume increase. "VOL-": Short to decrease the volume, long to continue the volume decrease. "NEXT": Short song "PREV": Short the previous song "PLAY": short to play/pause Special function description: "PLY": and hold for 3 seconds to force into pairing mode, and hold for 6 seconds to clear the pairing list Specifications:B:QCC5125 LDAC Colour:Green Material:PC Package Contents: 1 * amplifier board(The circuit board printing is slightly different, which does not affect the use) 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.