Boost Module: With -USB voltage input, you can get 9V 12V 18V 24V voltage by simply connecting the USB 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 setting module has DC 2-24V input and 5V-28V adjustable voltage output, and the conversion efficiency is as high as 93%. time a 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 supply with adjustable output, boost chargers, etc. Widely used in batteries, , DIY adjustable regulated supplies, industrial equipment, 5V, 9V, 12V, 28V output, etc. Note: The maximum output current is 2A. Please rotate 15 clockwise before . This is the direction to increase the voltage. When it reaches of the stroke, it will to make a clicking sound. Then you can turn it 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 the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.