Pre-Drilled Linear Shaft Assembly, System of Measurement Inch, Shaft Diameter 3/4 in, Shaft Length 48 in, Shaft Material Steel, Center Height 1.5 in, Rail Base Overall Width 1.75 in, Shaft Drilling Pre-Drilled, Support Rail Drilling Pre-Drilled, Rail Mount Hole Thread Size #10, Surface Roughness 8 uin