LED Numeric Display: Buck converter equipped with an LED voltmeter display. The voltmeter has a measurement error of ±0.1V. The input voltage range is from 4.0V to 40V, and the output voltage range is from 1.25V to 37V(Note: If the input voltage is below 4V, the onboard voltmeter will not operate and no display will be shown). The voltmeter can be switched off by holding the switch for over 1 second and less than 4 seconds, then releasing it. Once the voltmeter is off, just press the switch briefly to turn it on 2596 Adjustable Buck Converter: The internal oscillation frequency is 150KHz. It's a second-generation voltage regulator with low power consumption and high efficiency. It's equipped with high-quality solid capacitors to improve the stability and durability of the circuit and filter out high-frequency noise effectively Ease of Use: 2596 adjustable buck converter can easily adjust the output voltage with a mini screwdriver. It comes with terminal blocks for quick connections, so you don't need to solder if you don't want to Features & Safety: The input side of the 2596 buck converter is protected by two diodes. If you connect it backwards, it won't the module. It also has overheat and short-circuit protection. (For power over 15W, make sure to improve heat dissipation) Applications: The 2596 buck converter works great in lots of different situations, like car power supplies, projects, and industrial equipment. It's perfect for both pros and beginners