Users can also mount components such as sensors directly to the collar or mount the collar to metal plates. It has machined flats and tapped holes on the top and bottom of the collar allowing users to stack collars on top of each other when shafting must be perpendicular to each other.6250", Steel, OD 34mm Ruland clamp style shaft collars do not mar the shaft, are infinitely adjustable, and have superior holding power when compared to set screw collars. International series collars have metric outer diameter and width dimensions.