Material:SUS304 Stainless Steel Lead Screw + Brass nut Lead screw diameter: 8mm,Thread: Acme thread ,Lead screw spacing: 2mm Lead screw length: 500mm,Lead of thread: 4mm Application:Use for LCD DLP SLA 3D printer Z axis and CNC machine etc. Packege Include:2 pcs 500mm Tr8X4 Lead screw with T8 brass nut.