The Nikon MB-D15 Multi-Power Battery Pack is a Multi-Power Battery Pack grip for the Nikon D7100. The MB-D15 offers added ease of use with a shutter-release button, AE-AF lock button, multi selector, and main- and sub-command dials that can be used with the camera held vertically.
You can power the Nikon MB-D15 with either six AA batteries or EN-EL15 rechargeable Li-ion batteries. When using the MB-D15 with AA batteries, you need the Nikon MS-D14 AA Battery Holder. When using an EN-EL15 battery, you'll need the MS-D14EN Battery Holder.