POM material is durable and silent.Lead Screw Diameter: 8mm, Pitch: 2mm, Lead of thread: 8mm; two small M3 holes centre distance is 18mm 8mm lead T8 lead screw is with 4 starts. Package: 1 set T8x8 POM anti-backlash nut After-sale service: If there is any problems for this nuts, please feel free to message us or QA, we will provide you satisfied solutions. Item: T8 nut. Material: POM. Package: 1sets