Features: The first you need to install the 18650 flat for head then the button on the back of the circuit board to activate the use of this product. 5.5x2.1mm port output is for DC 12V,Suitable for wifi Router LED Strip Security Camera and more. As USB mobile for cellphone tablet and more devices,with for DC adapter,easy to use. With overcharge, overdischarge, overload, short circuit and other for protection. Specifications: Item Type: 18650 Li-ion Box Material: PC Color: Black Size: 9.5x12.5x2.7cm Input: DC12V-13V 5.5x2.1mm Port Output: DC12V 3-5A USB Output: 5V 2A Due to different product batches, the appearance , which not affect the use Package Contents: 1X DIY Box 1X Adapter Only the above package content, other products are not included. Note: Light reflection 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.