The Promaster Power Grip specially designed for the Canon 5D MK IV DSLR camera. It is equipped with an alternate shutter-release button, main dial, multi-controller, AF point selection button, AE lock button, AF start button, AF area selectinon button, and multi-funtion button for comfortable access to the 5D MK IV's controls while shooting in a vertical position. This power grip can hold two LP-E6 rechargeable lithium-ion batteries at a time. Two battery trays are included. Each tray holds 2 LP-E6 batteries. So you can pro-load the spare tray and change batteries ultra fast!