This grip is specially designed for the Nikon D850 DSLR camera. It is equipped with an alternate shutter-release button, main command dial, multi-selector, Fn button, Sub-command dial, and AF-ON button for comfortable access to the D850's controls while shooting in a vertical position. This power grip can hold two EN-EL15a rechargeable lithium-ion batteries at a time. Two Li-ion battery trays are included along with 1 AA battery tray. So you can pre-load the spare tray and change batteries ultra fast!