Features:  The voltmeter resolution: ±0.1V.  The voltmeter digital display range: 0V - 45V.  The voltmeter input voltage range: DC 4V - 40V.  Output voltage: continuous adjustable (1.3V -37V).  Output current: 2A ( Max 3A).  Size: 65 x 35mm.     Description:  With terminal block.  Over-heat protection and short circuit protection function.  LED digital voltmeter tube, it can adjustable accurate aimed at your multimeter.  Press the key "S1" to let the display show the input or output voltage. when the green led light, it shows output, the red show input. Touch the button to switch the measurement input or output voltage, and indicator light shows which voltage is being measured, it can save the settings, even if the power off and restart.  Using 150KHz internal oscillation frequency, belonging to the second generation switching voltage regulator, low power consumption and high efficiency.     Note:  To guarantee the accuracy of the voltmeter, make sure the input voltage above 4V.  The input voltage must be 1.5V higher than the output voltage or 1.5V above.     Package included:  5 x DC-DC 1.3V -37V 3A adjustable buck power module