Polyurethane is a harder material than stock to reduce handlebar twist while still providing good dampening characteristics. Four cones and four steel cupped washers included. These cones fit in all Ride Eng. KXF triple clamps as well as 2005-2014 stock KX250F; 2006-2011 stock KX450F triple clamps plus the D shaped pockets: 2015+ KX250/250x, 2012+ KX450/450x.