Fangrui Product Details With A Voltage Meter And Voltmeter Displays Self-calibration. Uses A More Advanced Microprocessor Voltage Voltmeter Error 0.05v, Range 0 - 40v. (to Accuracy Voltmeter, Make Sure The Input Voltage Of 4.5v And Above). Touch Of A Button To Switch The Input Or Output Voltage Measurements And Has A Light Show Which Is Being Measured Voltages, And Save The Settings, Even The Power Off And Then On. The Voltmeter Can Be Turned Off When Not Needed, Easily With The Touch Of A Button On The Left. With Terminal Blocks, It Can Be Used Easily Without A Soldering Iron, And The Connection Points Are Retained. Input Voltage 4.5- 40v. (input Voltage Must Be Higher Than The Output Voltage Of 1.5v Or More) Adjustable Output Voltage Range Of 1.25v - 37v Continuously Adjustable. (input Voltage Must Be Higher Than The Output Voltage Of 1.5v) Output Current 3a, Recommendations Within 2.0a Use, High Current Needed To Enhance Heat Dissipation. Output Power 20w, 15w, Please Enhance Heat Dissipation Over. High Conversion Efficie