KKmoon High Quality LM2596 DC 3A 4.0/40V to 1.25V/37V Red LED Voltmeter Adjustable Step-Down Power Module+4pcs Copper Holders and Screws Voltage Regulator Experimental Power Buck Converter 7 * 4cm

It's a adjustable step-down power module with red LED voltmeter. It can use conveniently without soldering iron and keep retain the wire bonding. 

Features:
4pcs copper holders and screws for free.
With power indicator light and red LED voltmeter of ±0.05V.
A key switch of the nixie tube, IN indicates input voltage, OUT indicates output voltage.
Green light: measuring the output voltage, red light: measuring the input voltage.
With wiring point, use conveniently without soldering iron and keep retain the wire bonding. 
Adopt 150KHz ripple frequency, low consumption and high efficiency.
Overtemperature and short-circuit protection.

Specifications:
Color: Green surface
Material: PCB
Input Voltage: DC 4.0-40V
Output Voltage: DC 1.25V-37V 
Output Current: 2A (normal and stable), 3A (Max).
Ripple Frequency: About 150Khz
Display Color: Red
Voltage Meter Error: ±0.05V
Measure Range: 4-40V 
IN+: Input Postive
IN-: Input Negative
Out+: Output Postive
Out-: Ouput Negative
Product weight: 33g / 1.2oz
Module size: 7 * 4 * 1.5cm / 2.8 * 1.6 * 0.6in (L * W * H)
Package weight: 37g / 1.28oz
Package size: 11.5 * 8 * 1.5cm / 4.5 * 3.1 * 0.6in (L * W * H)

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 List:
1 * Step-Down Power Module
4 * Copper Holders 
4 * Screws