"Hourglass" style kit is used in necks that are 7" long. Used on later stock Harley-Davidson frames and many aftermarket custom frames. Fits all Pro-One Triple Trees and other brands with 4 pre-drilled holes. On brands without the necessary holes, kit can still be installed by drilling and tapping 4 holes. Easy to follow instructions included. Bearing Race fits 1.990" neck bore. Measure the neck bore where the races install in the neck, or the length of the neck to be sure this is the kit you need. Press-in bearing cup style kit is used on many older Harley-Davidson frames and many custom aftermarket frames. Designed for necks that are 5-11/16" long (not including the cups). Includes Polished Stainless Steel bearing cups. Easy to follow instructions included. Bearing cups fit 1.325" neck bore. Measure the neck bore where the external neck cups install in the neck, or the length of the neck to be sure this is the kit you need.