The battery is equipped with a very convenient charging system that uses the built-in USB-C port. Typically, LED STINGRAY MARK II sets with rechargeable 21700 Li-ion batteries come with a USB-C cable, which can be used to charge the battery from any power source (charger, power bank, laptop, desktop computer, or a car USB charger). The battery can also be charged with chargers dedicated to standard 21700 Li-Ion batteries. Additionally, there is a built-in bi-color LED in the positive pole of the battery. It informs the user about the current charging status (red indicates the charging process / blue means that the battery is fully charged). Due to the lack of memory effect, the batteries can be recharged at any time without negatively affecting their capacity and battery life.