these nuts are compatible with Prusa i3 MK3 MK2 MK2S 3D Printermetal material is durable and silent.Lead Screw Diameter: 8mm, Pitch: 2mm, Lead of thread: 8mmColour: blackMaterial: metalPackage Contents:2 sets x POM nut kitOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.