Check the listing for details. 2PACK 8mm to 8mm Bore Shaft Coupling Rigid Coupler Connector Silver New. Condition: New. Listed at 13.02 USD. Rigid Shaft CouplerGeneral Information：[1]Single piece set screw clamp design makes it easy to set up the items on the shaft and control the holding capacity of the coupling.[2]Widely used in blowers,3D printer,DIY robots,CNC machine,stepper motors,etc. Similar to rigid clamp couplings, shaft couplers are used to hold bearings and sprockets tightly on the shaft, and are used in motor and gearbox assemblies.[3]Top tight type rigid coupling with 2/4 screws to hold the shaft tightly; high torque with rigidity, low inertia and excellent sensitivity.[4]NOTE: The rigid type basically does not allow eccentricity, and it must be fully adjusted during use.[5]Connection Diameter: 8mm to 8mm, Total Length: 22mm /0.87 inch, Outside Diameter : 14mm/ 0.55 inch.