An SFI Approved Aluminium quick release steering wheel boss with a steel splined hub to suit 3 bolt steering wheels with three 5/16" Mounting holes on a 1-3/4" bolt circle (hole distance 1-1/2" center-to-center). The 360° Collar allows easy release and the slug with it's SFI Approved 2" long spline is also available separately and has a 3/4" bore.