Du-Bro White Three Blade Spinner 3" \(76.2mm\) Part No: 550. Simple, easy and safe to install. Each Spinner comes with5 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.