ITEM NAME:Dual USB 5V 1A 2.1A Mobile Power Bank 18650 Battery Charger PCB Module Boar V8K4 Dual USB 5V 1A 2.1A Mobile Power Bank 18650 Battery Charger PCB Module Boar V8K4 This item is for what use. 100% Brand New and High Quality This is the mobile power module Accessories, 18650 Circuit board. Meet the individual needs of your DIY, but you must understand basic electronic assembly. Motherboard comes with protection function: Charging overcharge protection, over-discharge protection, overcurrent protection. Mini USB input: 5V 1A USB Output: 5V 2.1A / 5V 1A(Dual USB interface) Charging display: intelligent digital display Batteries Type: liquid lithium-ion batteries (18650) Product Size: 57mm x 28mm Screen size:27mm x 17mm Installation instructions: The circuit board is connected to the battery negative B-, B + is the positive, do not connecting reversed, connecting reversed will burn the board, the battery is connected in parallel welding, assembling battery. Note that the insulation between the battery and the circuit board, battery lead not to touch the circuit board, so as not to cause a short circuit. Material: CCL Color: Black Quantity:1 PC Net Weight: 10g Package Contents: 1 x Battery Charger PCB Note: Light shooting 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..Batteries Type: liquid lithium-ion batteries (18650). USB Output: 5V 2.1A / 5V 1A(Dual USB interface). Mini USB input: 5V 1A. The circuit board is connected to the battery negative B-, B + is the positive, do not connecting reversed, connecting reversed will burn the board, the battery is connected in parallel welding, assembling battery.