Specification:
Module Model:LM2596 Buck Converter Voltmeter
Input Voltage: DC 4.2~40V
Output Voltage: 1.25V~37V
Output Current: 2A(normal and stable), 3A Max.
Ripple Frequency: About 150Khz
Ripple Peak: About 100mV
Display Color: Red
Voltage Meter Error: ± 0.1V

Features:
There are output voltage adjustment "-" button for decreasing output voltage and output voltage adjustment " " for increasing output voltage.
There are two LED indicators on this converter board, including the red LED and the green LED. The red LED will light on when you measure input voltage and green LED will light on when you measure output voltage.
Low power consumption, with terminal and retain the wire bonding wiring point. And If you remove the P3 jumper cap, the voltmeter will shutdown.
High Precision: The buck converter consists of 36u thickened circuit boards, high-Q inductance with output LED indicator, and superior solid-state capacitors that can effectively filter out high frequency noise. Suitable for various electronic projects.
Easy to DIY: Connect to power source, using a mini screwdriver to increase or decrease output voltage by adjusting the screw on the blue potentiometer and monitor voltage with multimeter to get the needed voltage, clockwise to step up voltage and counterclockwise to step down voltage. (Factory default stays a high voltage, you need to contrarotate about 7-15 circles before the voltage starts ramping down, 1 circle means +/- 1V).

Wiring connection:
IN : connect IN to your Input Positive
IN-: connect IN- to your Input Negative
Out : connect OUT to your Output Positive
Out-: connect OUT- to your Output Negative