Feature 1 Firm Connection: The coupling can connect two shafts with different diameters or one motor shaft for firm and stable connection. 2 Efficient Works: Fix the bearing and sprocket tightly on the shaft and reduce the stress when shafts are not in good alignment. 3 Extensive Using: Allows for wide application on blowers, 3D printers, DIY robots, CNC machine tools, stepping motors and more. 4 Perfect Fitting: Suits perfectly for NEMA 17 step stepper motor, the coupler connector has 14mm diameter as well as 25mm length. 5 Including 10Pcs: Made from premium aluminium alloy material, all the 10pcs enable very convenient replacement and installation.Item Type: Shaft CouplingProduct Size: Approx. 25 x 14mm / 0.98 x 0.55in (L x D) Application: Applicable to 3D printers, motor couplings, ship models, aircraft models, car models, engraving machines, etc. Product Adaptive Motor: 42 Stepper MotorShaft Locking Mode: Screw fixed type. Package List10 x Shaft CouplingNote1. The rigid design basically does not allow eccentricity, and must be fully adjusted during use. 2. The design of single piece fixed screw clamp is convenient for setting items on the shaft and controlling the holding capacity of the coupling.