Features: This is a 5A high power high efficiency DC-DC buck module with low ripple and converts 4.0V~38V to 1.25V~36V. The voltmeter on board can be self calibrated; using more advanced voltage microprocessor, voltmeter error is ±0.05V, measuring range of 0~40V. Input and output have screw terminals for convenient connection even with no soldering iron, and keep solder pad for soldering connection. It supports overheating protection and short circuit protection function. Comes with heat sink for better heat dissipation, and several standoffs and nuts. Specifications: Input Voltage: 4.0V~38V (input voltage should be at least 1.5V higher than the output voltage) Output Voltage: 1.25V~36V (continuously adjustable) Output Current: Max. 5A(4.5A or less is suggested) Max. Output Power: 75W Max. Efficiency: 96% (Efficiency is related to input/output voltage, current and voltage difference) Load Regulation S(I): ≤0.8% Voltage Regulation S(u): ≤0.8% Size: 60*36*18mm/2.36*1.41*0.7" Voltmeter Self-calibration Instruction: 1. When the voltmeter on board displays output voltage, press and hold the right button for 2 seconds to enter output voltage regulation mode, and the voltmeter display and output voltage indicator light synchronously flash.Similarly, when the voltmeter on board displays input voltage, press and hold the right button for 2 seconds to enter input voltage regulation mode, and the voltmeter display and input voltage indicator light synchronously flash. 2. Press the right button to increase voltage value, and left button to reduce voltage value.Due to a unit of voltage is less than 0.1 V, so you need to press button for 1 time~5 times to see the voltage value changes 0.1V. 3. After voltage adjustment, press and hold the right button for 2 seconds then release to exit voltage calibration mode. All the parameters set up will be automatically saved if power failure. Note: To ensure that the voltage meter accuracy, please make sure that the input voltage is above 4.5V Package Includes: 1 x Step Down Module 1 x Heatsink 4 x Standoffs and Nuts