The positive pole of the Weltool UB18-33 battery has a protection circuit and a USB-C charging port. You can use a 5V adapter to charge the battery directly, or you can use a  power bank to charge the battery. You can also put the battery into a lithium-ion charger to charge it. There is a charging indicator on the top of the battery to indicate the charging status. The red light means it is charging, and the blue light means it is fully charged.

Model: UB18-33

Nominal capacity 3300mAh

Rated capacity: 3200mAh

Finished product internal resistance: ≤100mΩ

Voltage: 3.6V

Maximum continuous discharge current: 8A (10-25℃)

Charging current 1.3A (Type-C USB charging)

Overcharge protection cut-off voltage: 4.25±0.05V

Over-discharge protection cut-off voltage: 2.5±0.1V

Cycle charge and discharge times: 70% capacity after 300 charge and discharge cycles

Charging temperature: 0-45℃

Discharge temperature: -10-60℃

Storage temperature: -10-60℃

Finished product size: 18.8±0.2 mm (diameter), 69.8±0.2 mm (length)

Weight 50±0.5g