Us Sbr20 Linear Rail Set+3 Ball Screw Rm1605-350/650/1050+bk/bf12+coupler Cnc Fine Workmanship Heavy-Duty Material Complete Linear Guiding System Simple Installation Quiet Operation Extensive Application Screw Diameter: 0.63 in / 16 mm,Screw Length: 7.87 in / 200 mm,Class: C7,Packing Size: 44 x 8 x 4 in / 110 x 20 x 10 cm,Linear Guide SBR20 Length: 11.8/23.6/39.4 in (300/600/1000 mm),Screw Pitch (Lead): 0.197 in / 5 mm,Feature: Anti-friction,Ballscrew Length: 14.8/25.6/41.3 in (350/650/1050 mm),G.W.: 44 lbs / 20 kg