The CLF456 Replacement Foot for Select Canon Lenses from NatureScapes replaces the stock foot of your large telephoto lens with this Arca Swiss-style foot for easy attachment to a corresponding quick-release clamp. The replacement foot is made of strong 6060 aluminum alloy and provides greater stability and easier removal. Two removable safety screws prevent the lens from sliding out of the clamp in the case of inadvertent loosening. The CLF456 replacement foot is compatible with all Arca-Swiss type heads and is designed to fit the following lenses: Canon EF 400mm f/2.8L IS II, EF 500mm f/4L IS II, EF 600mm f/4L IS II. This foot also fits original Canon EF 500mm f/4L IS, EF 400mm f/2.8 IS and EF 600mm f/4 IS, and may also fit other Canon lenses. For legacy lenses shorter screws may be necessary.