Schmitt & Ongaro Primus Steering Wheel. Stainless steel. Designed to deliver maximum ergonomic all-day comfort. Engineered for long-lasting, uncompromising durability. Complements any helm. Manufactured using a unified investment casting, including the integrated ring, for massive strength. UV-resistant black Santoprene rubber provides all-weather control and comfort. Underneath, finger grips deliver a sure, solid grip. The rim is slightly thicker than most other wheels. Standard 3/4" tapered hub. Comes with a lifetime warranty on the corrosion resistant stainless steel and three-years on the Santoprene rubber grip and inserts. Center nut not included. 15.5".