Du-Bro White Three Blade Spinner 2-1/2" (63.5mm) Part No: 545. Simple, easy and safe to install. Each Spinner comes with 5 shaft adapters (5mm, 6mm, 1/4", 7mm, 5/16"). Features a unique, nylon insert lock nut design for attaching the back plate and spinner - giving a solid & secure hold. Designed with safety in mind.