Nikon BL-3 Battery Chamber Cover for Nikon EN-EL4 and EN-EL4a for the MB-D10
The Nikon BL-3 battery chamber cover is required when the EN-EL4 rechargeable battery is paired with the MB-40 battery pack or MB-D10 multi-power battery pack. The cover--which clips onto the battery--replaces the standard tray that comes supplied with the battery pack. The BL-3 comes with a neoprene storage pouch.