Specifications:Material: Stainless steel lead screw， copper nutScrew diameter: 8mmLength: 500mmScrew spacing: 2mmLead of thread:8mmRange: Reprap makerbot 3d printer accessories 3D engraving machine lead screw 500mm length with nut.Nut turn an around move 8mm Package include:1x 500mm lead screw1x Brass Nut