Wimberley AP-553 Replacement Lens Foot Replaces the factory foot of your lens, lowering the center of gravity for optimal balance Adds a built in double dovetail for Arca Swiss compatibility For Nikon 200-400 VR Lenses and Nikon 500 f/4 AF-S I,II and VR Lenses Anodized 6061 Aluminum, stainless steel fasteners Made in USA. Assembled in Charlottesville, Virginia