Rechargeable18650 Li-ion Battery 3.7v (Recycled) Relay Module You can use it to

You can use it to connect some serial device to your PC via USB port

The MINi RC522  can be used for almost all kinds of 13

Power Source : Corded Electric

VCC   For 5v  if use with 5v level system Such as ( Arduino UNO

Rechargeable18650 Li-ion Battery 3.7v (Recycled) Relay Module You can use it toIntroduction : Li Ion 18650 cylindrical rechargeable batteries. Used for device needs 3. 7V power Building portable power device that needs high energy density and low weight Product Specifications Capacity. You can connect more than one to get more voltage or current. Features : Type : Lithium Ion . Voltage : 3. 7 V. Battery Capacity : 2200 mAh.