The MB-D17 is a multi-power battery pack that extends the autonomous operating time of certain Nikon DSLRs. Use of this battery pack also facilitates more comfortable handling when shooting in portrait mode. The pack features alternative shutter-release, multi-selector and AF start buttons for use when holding the camera in the vertical shooting position, as well as secondary main- and sub-command dials. It can be powered by Nikon’s EN-EL15 Li-ion battery or six AA-size standard batteries. When using the optional BL-5 battery adapter, the MB-D17 can also be powered by Nikon’s EN-EL18/EN-EL18a Li-ion batteries, which are compatible with Nikon’s flagship D4-series cameras and the D5.