Screw mainly used in stepper motors, machine tools and other equipment. Screw without processing, directly connected to the bearing. Suitable for industrial automation equipment, stepper motor rails; such as 3D printers; engraving machine; Module; slide; elevators etc. Color: Gold + Silver Lead Screw: Material: Stainless Steel Diameter: 8mm Spacing: 2mm Total Length: 500mm Screw Nut: Material: Brass Diameter: 8mm Mounted Ball Bearing: Material: Zinc Alloy Bore Diameter: 5mm Hole Diameter: 8mm Total Length: 55mm Height: 29mm Shaft Coupling: Material: Aluminum Shaft: 6.35 x 8mm Length: 24mm Diameter: 18mm How Install: 1. Pls put the screw nut into the lead screw 2.Then the 2 mounted ball bearings should be installed separately at both ends of the lead screw 3. According to the size, you should adjust the distance between the nut and the mounted ball bearing 4. Place the shaft coupling into the lead screw next to the mounted ball bearing Package Included: 4x Lead Screw 4x Screw Nut 8x