Restore power to your Nikon EN-EL14, EN-EL14a, and EN-EL15 lithium-ion batteries with this compact UNK1 Dual-Slot USB Travel Charger from Nitecore. It operates on 5-VDC input power, and features an attached USB cable stored in a trough to save space and prevent damage. The USB connector allows for connection to one of various user-supplied adapters, portable power banks, and solar panels. The device has a second slot on the rear to accommodate a backup battery.

The sophisticated UNK1 contains a smart charging management system, which monitors battery types, capacities, and initial internal resistance, then automatically applies the most appropriate charging current based on this data. The device also provides battery-condition monitoring, carrying out a health inspection based on resistance at the time of installation. A cell's health bar will appear on the LCD display, which also shows capacity, voltage, and percentage of charge completed. When a battery's health has declined to the lower limit, the bar will start flashing to alert you that it should be replaced.

The UNK1 offers a mechanical reverse polarity protection mechanism that prevents charging from occurring if an incompatible or incorrectly installed battery is present. The error message "EE" will appear on the LCD to notify you in the event that a short-circuited battery is detected. Another helpful feature is the battery recovery mode that restores dormant cells to active duty.

Built for durability, the UNK1 is made from polycarbonate and ABS plastics that are corrosion resistant and fire retardant. When this toughness is coupled with the convenient compactness and considerable versatility of the UNK1, the result is a charger that is useful for travel, camping, and many other adventures.