Wimberley AP-554 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 Lens 200-400 f/4 AF-S VR I & II and 500 f/4 AF-S I,II,VR I & II and Nikon 300 F/2.8 VR Anodized 6061 Aluminum, stainless steel fasteners Made in USA. Assembled in Charlottesville, Virginia