Check the listing for details. 2 Pcs 5mm to 5mm Bore Coupling Set Screw Red. Color: Red, Condition: New. Listed at 14.15 USD. stepper shaft couplingGeneral 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: 5mm to 5mm, Total Length: 20mm /0.78 inch, Outside Diameter : 12mm/ 0.47 inch.