The OM System UC-90 is a USB battery charger built for the LI-92B lithium-ion battery used in TOUGH-series cameras, including the TG-7. It charges via a standard USB connection, allowing power from a wall adapter, computer, or portable power bank rather than requiring a dedicated AC outlet. This makes it a practical option for travel, giving divers and outdoor users a way to top up a spare battery without carrying separate mains charging equipment.