1 Wide range of applications 2 APP has a timer shutdown function 3 Supports custom 10-segment sound effects to be adjusted arbitrarily to make up for the deficiencies, so that different speakers can achieve better sound effects. 4 The mechanical switch can be turned off with one turn, no need to wait for a long time, which is convenient and fast. 5 Support APP. Modify and change for Bluetooth name, password setting, volume adjustment of prompt sound, on/off prompt sound, sleep aid, sound effect selection + custom sound effect, U disk playlist Adapter power supply: 9-24V/3A (can not be connected to AC) Bluetooth version: 5.1 Audio input: BT+AUX+USB+USB sound card Audio output: left channel 30W + right channel 30W Volume adjustment: classic mechanical knob (with volume scale), stepless adjustment Switch machine: classic mechanical switch, one turn switch machine, no need to wait for a long time. Adapter speaker: 10-50W 8Ω Protection mechanism: overheating, overcurrent, short circuit, anti-static protection Colour:Black Material:ABS Package Contents: 1x Bluetooth digital amplifier board module (Delivery is in parts) 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.