The P-40 is a 5.88” long, double dovetail, Arca-Swiss style quick- release plate. It is used to connect a camera lens, fitted with both a rotation collar and tripod mounting foot, to a compatible quick-release clamp. Wimberley plates are compatible with most Arca-Swiss style quick-release clamps, such as those made by Wimberley, Really Right Stuff, Kirk Enterprises, Markins, Arca-Swiss, Foba, Graf and others.