Allows use of EN-EL4/EN-EL4a battery with MB-D10 Multi-Power Battery Pack for D700, D300S, D300 and MB-40 Multi-Power Battery Pack for F6.
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.