Material: Aluminum alloy; Connection Diameter: 3mm to 6., 35mm; Total Length: 25mm /0., 98 inch; Outside Diameter : 19mm/ 0., 75 inch , Zero backlash. Connection Bore Diameter: 3mm to 3mm,Total Length: 25mm/0.98 inch,Outside Diameter: 19mm/0.75 inch,Material: Aluminum Alloy,Color Zero backlash. Buy Beam Online on Martinique at Best Prices Aluminum Shaft Coupling Uxcell 5Pcs 3mm To 3mm Aluminum Alloy Shaft Coupling L25xD19 Encoder Coupling Specification:Color: Silver ToneMaterial: Aluminum alloyConnection Diameter: 3mm to 6., 35mmTotal Length: 25mm /0., 98 inchOutside Diameter : 19mm/ 0., 75 inch Package Content:1 x Shaft coupling uxcell 8mm to 8mm Shaft Coupling 30mm Length 25mm Diameter Stepper Motor Coupler Aluminum Alloy Joint Connector for 3D Printer CNC Machine DIY Widely used in drive systems for encoders, instrumentation,lead screws, small pumps, feed rollers and anywhere light to medium duty, torsionally flexible coupling is required. For little torque shaft connect.