1. With voltmeter display, voltmeter error 0.1V, range 5-35V. (Note: if the input voltage is lower than 4.5V, the onboard voltmeter will not work and will not display) 2. Touch the button to switch to measure the input or output voltage, and the indicator light will show which end voltage is being measured. When the machine is turned on for the first time, the digital tube displays the input voltage by default, 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 it will keep the last setting, even if the power is turned off and then turned on. 3. The voltmeter can be turned off by pressing the switch for more than 1 second and less than 4 seconds, and then releasing it. After the voltmeter is turned off, just press the switch shortly to turn on the voltmeter. 4. This module can be used in the boost field where the output voltage is higher than the input voltage, such as batteries, power , DIY adjustable voltage regulators, 24V vehicle-mounted notebook power supplies, industrial equipment step-down, 9 to 12V, 12V to 18V, 18V to 24V, etc. Module properties:Non-isolated boost (Boost) Rectification :Non-synchronous rectification Input current:4A (maximum), no-load 18mA (5V input, 8V output, no-load less than 18mA; The higher the voltage, the greater the no-load current). Conversion efficiency:Less than 94% (the greater the voltage difference, the lower the efficiency) Switching frequency:400kHz Output ripple:50mv (the higher the voltage, the greater the voltage, the greater the current, and the greater the ripple) Load control:0.5% Voltage regulation rate:+0.5% Operating temperature:-40+85 Note:Due to different production batches, there are differences in silk screen printing/appearance, which does not affect usage. Colour:Blue Material:PCB+electronic components Package Contents: 1 * Adjustable Booster module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.