DC-DC Adjustable Buck Converter Step Down Power Supply Module LCD with Shell Feature: Beautifully acrylic Enclosure. Using STN liquid crystal display screen, Voltage and Current can be displayed simultaneously, blue background and white character, wide angle and wide field of view. Using button adjustable voltage, left button to reduce the voltage, the right button to increasing voltage. press button one time can adjust 0.04V voltage, press and hold more than 1 second to quickly adjust voltage. Calibration Mothod: Power-off status, press and hold the left button access the power, the display starts flashing, release the left button. using multimeter measured the output terminal voltage, if the measured voltage is greater than 5V, press the left button reduced the voltage to 5V; if the voltage is less than 5V, press the right button to increase the voltage to 5V. When the LCD display voltage of 5V sometimes it shows 4.99V , turn off the power, the calibration is complete. Performance: Input Voltage: 5~23V, Max 23V, recommended to use within 20V Input voltage must be higher than the output voltage 1V above. Please check the input positive and negative polarity before connecting, reverse may damage the components Output Voltage: 0~16.5V adjustable It can save the last set voltage automatically Peak Current:Recommended use in 2A, accuracy of 1%, the minimum display 0.01A, less than 10mA will not be  displayed. Peak Current: 3A Recommended use in 2A, accuracy of 1%, the minimum display 0.01A, less than 10mA will not be displayed. Conversion Efficiency: 95% Load Regulation S I ≤0.8% Voltage Regulation S U ≤0.8% Size: 62 x 44 x 18mm Package including： 1 x DC-DC Adjustable Step-down Power Supply Module 1 set x Enclosure Kits (case cover is bigger than item, please accept it before you purchase)