This prop holder is a must if you carry spare propellers. It consists of a round stainless steel base, with a 3/4Ó diameter solid center post, welded both sides. The center post is threaded at the top end, and holds an appropriate polished stainless steel washer, which is held tightly against the prop by a chromium plated brass lock nut. We chose brass for this task in order to minimize the risk of thread galling. The entire assembly is mirror polished. It is available in standard size, which holds outboard and Alfa and Bravo sterndrive props, and Ôlong hubÕ, for Speedmaster size props. They are designed to mount on a horizontal surface, with the props on top of the base.