I purchased the battery holders for the Nikon D7000 and the D3100. Nikon makes a battery holder for the D7000 but not the D3100. I am a professional photographer and uses these cameras as back up and the D3100 for IR Infrared photography. REVIEW: Agfa Battery holder for the Nikon D7000, D7100 Would I recommend this unit, YES. The Agfa unit fits fine, gives it good balance when using a zoom or longer telephoto lens. The battery pack is recognized immediately with a BP appearing next to the battery Icon on the LCD display. The battery in the holder is used first and then the battery in the camera. I can shoot all day with GPS, Auto-focus and VR On without worrying about replacing the battery. I used Nikon OEM batteries and have no idea how non-OEM batteries would work.