2pcs T8 Anti Backlash Spring Loaded Nut Elimination Gap Nut Z-axis for Upgrade Ender 3 Ender 3s Ender 3 Pro V2 CR-10 Tornado 3D Printer 8mm Acme Threaded Rod Lead Screw Diameter: 8mm, Pitch: 2mm, Lead of thread: 8mm; two small M3 holes centre distance is 18mm Made of high quality brass and stainless steel material, more durable. Special anti backlash nut, high precision, low cost DIY engraving machine, 3D printer preferred. xirbbo 2pcs T8 Anti Backlash Spring Loaded Nut Elimination Gap Nut Z-axis for Upgrade Ender 3 Ender 3s Ender 3 Pro V2 CR-10 Tornado 3D Printer 8mm Acme Threaded Rod