Power Bank Circuit Board, Stable 3 USB Power BankCircuit Board, Mobile Phone Batteries for 3.7?4.2V

Feature:1. With 3 USB charging port, can charge 3 mobile phones at the same time 2. Using dual IC control, synchronous rectification, conversion rate up to 90% 3. Using high?quality inductors and dual?tube rectifiers, with stable performance 4. With over?discharge, over?charge, and overload protection circuit functions 5. Can automatically identify the output current of 5V1A or 2A according to the device, suitable for 3.7?4.2V rechargeable lithium batteries, such as mobile phone batteries, 18650 batteries, etc. Specification: Item Type: Power Bank Charger Module Material: Synthetic cardboardPower Supply Voltage: 5V 2.1APower: 2.1ANumber of Pins: 2 Package List:5 x Power Bank Charger Module Notice: 1. Connect the positive pole of the lithium battery to B+, and connect the negative pole of the lithium battery to B? 2. Note that the B+ and B? of the boosted battery must not be connected reversely, they will burn 3. The Micro USB port needs to be activated once for the first use