2 pcs Electronic Accessories: 1 x Buck module & 1 x Digital Amplifier Board and high quality. The power supply voltage is 2.5-5.5V, more than 5.5V, the chip will burn out.The power supply current recommended 1A or more, less than 1A sound will be small. The positive and negative poles of the power supply can not be reversed, and the reverse chip is burnt.The load recommended 4 Euro 3W speakers. This module has a mute switch, high level mute, low level playback, the default is low level playback. This module is suitable for amplifying the audio signal of 0.5V-1V. If the signal is too small, it needs to be connected to the preamplifier.This module is only suitable for single-supply operation and cannot be connected to a negative power supply. color: blue+Black Material: plastic + metal Output voltage: default 5 V, automatically adjust between 3-12 V after fast charge activation Output power: up to 24 W (5 V / 3.4A, 9 V / 2.5 A, 12 V / 2A, etc.) Output voltage for compensation function cable Conversion efficiency: 90% -97% Support for multiple fast charging protocols Digital Amplifier Board: Working voltage: 2.5-5.5VDC Working current: 1A or more Output power: 3-5W Load parameters: impedance 4-8 Ohm, speaker power 3-5W Signal to noise ratio: 85dB@ VDD=5V, Vorms=1V Dimensions: 1.2x1.5cm/0.47x0.59 inch Buck module: Overvoltage input and undervoltage protection Input overcurrent protection Maximum output current, short circuit protection Machine over temperature protection Quick charge support agreement Support DCP protocol, BC1.2, Apple, Samsung protocol Huawei Support Fast Upload FCP / SCP Protocol Huawei Support Protocol Fast Charge AFC Support Spreadtrum Protocol Fast Load SFCP Qualcomm QC2.0 and 3.0 support MTK support PE1.1 / PE2.0 size: 50 x 40mm Package Contents: 1 x Buck module 1 x Digital Amplifier Board Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture