Specification Brand : KUAOXK BulletPoint1 : 1. Made of aluminum alloy, lightweight, anti-oxidation, CNC cutting, outstanding appearance, high-precision workmanship, and long service life. BulletPoint2 : 2. Provides torque transmission and alignment, efficient coupling design. BulletPoint3 : 3. Widely used: used to transmit motion, widely used in small CNC machine tools, 3D printer Z-axis couplings, etc. BulletPoint4 : Inner Diameter:3mm,3.17mm,4mm,5mm,6mm,6.35mm BulletPoint5 : Hole Compression Nuts: Four-hole lock nuts are fastened with a four-hole flange, which is more secure and can be used longer. This is intended to distribute the pressure of the nut to the fixed parts, reducing the risk of damaging the parts and reducing the risk of being damaged by tighten. Color : One Color ExternallyAssignedProductIdentifier : 8055477131438 ItemName : Rigid coupling,Stainless steel rigid coupling 1pcs D16L28 CNC Aluminium Alloy for Stepper Motor Coupler Shaft Couplings 3D Printer Couple(5X8) ItemPackageDimensions_Height : 1 centimeters ItemPackageDimensions_Length : 3 centimeters ItemPackageDimensions_Width : 2 centimeters ItemPackageQuantity : 1 ItemTypeKeyword : set-screw-couplings Manufacturer : KUAOXK Material : Metal ModelNumber : KUAOXK NumberOfItems : 1 NumberOfPieces : 1 PartNumber : KUAOXK ProductDescription : 1. The flexibility of the coupling eliminates stress between the motor and the driven components. 2. High strength, strong plasticity, good heat resistance and good toughness. 3. A shaft coupling is a coupling that connects two shafts together to transfer torque and rotational motion.