These batteries charge through a USB port. These batteries are not like any other re-chargeable battery. These batteries only take one hour of less to charge rather than other ones that sometimes take days. All you have to do is plug a USB cord with two of the same ends into the batteries and one into a power source and it will start charging quickly.
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SomeoneĀ engineered this battery so it could charge through USB and be a faster charging battery than other portable charging models.