ITEM NAME:2-USB 5V 2.1A Mobile Power Bank 18650 Battery Charger Board LCD Digital Module 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. Intelligent output device after charging full, automatically stop charging, to prevent mobile phones overcharge. Output voltage and current stable, will not harm user devices. 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. Specifications: Material: Electronic components Color: shown as pictures Size: 63×26×13mm/2.48×1.02×0.51in (Approx.) Screen size: 27mm x 17mm Micro 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) Quantity: 1 PC Note: 1.Transition: 1cm=10mm=0.39inch 2.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you.Batteries Type: liquid lithium-ion batteries (18650). USB Output: 5V 2.1A / 5V 1A(Dual USB interface). Micro USB input: 5V 1A. 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.