Boost Module: With -USB voltage input, you can get 9V 12V 18V 24V voltage by simply connecting the USB power adapter. Note: This is a boost converter module, so the output voltage should be at least 2V higher than the input voltage Adjustable voltage: The power setting module has DC 2-24V input and 5V-28V adjustable voltage output, and the power conversion efficiency is as high as 93%. Every time a new voltage is passed, it will remain at the original voltage you set, will not automatically reset, and will not bother you to adjust each time. Widely used: These boost boost converter modules can be used to fix emergency lights, electronic equipment, DIY a mobile power supply with adjustable output, boost chargers, etc. Widely used in batteries, power , DIY adjustable regulated power supplies, industrial equipment, 5V, 9V, 12V, 28V output, etc. Note: The maximum output current is 2A. Please rotate 15 clockwise before use. This is the direction to increase the voltage. When it reaches of the stroke, it will start to make a clicking sound. Then you can turn it down to the voltage you want. Colour: blue Material: plastic Package Contents: 5 x Boost converter with -USB Only the above package content, other products are not included. Note: Light 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.