The LP-63NSG Replacement Lens Foot with KES Sure Grip Coating for AF-S NIKKOR 500mm f/4G ED VR Lens from Kirk slides directly into the lens collar mount and locks into place by tightening the locking knob. The lens foot is compatible with most Arca-type clamps and heads. The double-dovetail design allows other Arca-type accessories to attach to the bottom or the top of the foot. The foot also allows the lens hood to mount in the reverse without bumping into it, for storage. The 6061-T6 aluminum foot has a black anodized finish including Sure Grip powder coating, which makes it resistant against scratches and corrosion. In addition, safety stops located on the bottom of the foot prevent the lens from accidentally being pulled when the clamp is partially open.