feature:With voltmeter display, voltmeter error 0.1V, range 4 ~ 40V. (Note: If the input voltage is lower than 4V, the onboard voltmeter does not work and does not displayLarge volume 5*5 touch the button to switch the measurement input or output voltage, and there is an indicator light to show which terminal voltage is being measured. When it is turned on for the first time, the default digital tube displays the input voltage, and the input indicator IN is on; touch the button, the digital tube displays the output voltage, and the output indicator OUT is on. and keep the last setting even after power offThe voltmeter can be turned off. Press and hold the switch for more than 1 second but less than 4 seconds, release it to shut down. Once the voltmeter is off, simply press the switch to turn on the voltmeter.Input and output voltage measurement error calibration function, press and hold the switch for more than 4 seconds, and then enter the voltage measurement error calibration function after letting go. At this time, the IN light is on (calibration input terminal), and the digital tube flashes to display the correct value (the factory parameter is 0.0). At this time, short press the button to change the value (the value range is -0.5~0.5, the unit is V), a positive number means upward calibration, Negative numbers indicate downward calibration. After adjusting the calibration value of the input terminal, press and hold the button for more than 2 seconds, and then let go to the error calibration of the output terminal. At this time, the OUT light is on (calibrating the output terminal), and the calibration value of the output terminal is displayed. The adjustment method is the same as the input terminal. After the calibration value of the output terminal, press and hold the button for more than 2 seconds. After letting go, the set value is saved, and the voltage returns to the normal display voltage. The set calibration value will take effect immediately and will not be lost after power off. (With this function, you can meet your higher precision requirements)5. With terminals, no soldering iron, easy to use, reserved solder connection pointsThe input voltage must be more than 1v higher than the output voltage6. Using the internal 150KHz oscillation frequency, it belongs to the second generation switching regulator, with low power consumption and high efficiency7. The input terminal has diode protection, and the reverse connection will not burn the module8. With overheating protection and short circuit protection more than 15W, please strengthen heat dissipationNumber of pieces shipped: 1 pieceProduct color: as shownProduct size: 66mm* 36mm* 14mm