Features 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. With over‑discharge, over‑charge, and overload protection circuit functions Using high‑quality inductors and dual‑tube rectifiers, with stable performance Using dual IC control, synchronous rectification, conversion rate up to 90% With 3 USB charging port, can charge 3 mobile phones at the same time Specification: Item Type: Power Bank Charger ModuleMaterial: Synthetic cardboard Power Supply Voltage: 5V 2.1A Power: 2.1A Number of Pins: 2 Package List:5 x Power Bank Charger Module Note: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 burn3. The Micro USB port needs to be activated once for the first use Package List 5 x Power Bank Charger Module