ROUND TAPER LOCKS MACHINE FROM THE PARTING LINE Exclusive top mount design of the Counterbored Round Taper Locks provides room for waterlines underneath.Advanced standard features Progressive’s Z-Series proprietary materials and treatments.Available in five diameters from 1/2″ to 2″. For more info, links to Catalog Pages and CAD Geometry: OTHER TAPER LOCK STYLES Threaded Taper Locks Rectangular Taper Bar Locks