Kastar Pro Multi-Power Vertical Battery Grip + 2x EN-EL14 EN-EL4a Replacement Batteries + Charger Kit for Nikon D3100, D3200, D3300 Digital SLR Cameras Kastar Pro Multi-Power Vertical Battery Grip can be used 1 or 2 EN-EL14 lithium batteries, to meet user needs for long time continuous shooting When using two batteries, the grip will automatically switch to the second battery if the first becomes depleted. Switching does not interrupt camera operation. variety of operating controls: shutter button, Main Dial, multi-controller, AF point selection button, AE lock/FE lock button, AF start button, and multi-function button. Make photographers easily control to shoot vertical and horizontal, shooting can get the same feeling when handling, really stable when the photographer using for heavy weight lenses Same functions as the original battery grip, include 30-day Money Back and one year Warranty.