This is an interesting prop driver. Comes with sleeve locker adhesive. It's intended to be "glued" onto your shaft. This gives you the shortest adapter possible. Originally designed for the Gunther props, will work with all the 4mm bore GWS props as well such as the ever popular 4x2.5 prop. Overall Length .474" (12mm). Max prop hub thickness about .350" (8.88mm) SKU Number: MPJ4500