This 19-slot Picatinny rail measures 7.67" (194.8mm) in length and 0.374" (9.5mm) in height. Now with three base profiles to choose from. We offer flat for universal or custom fit, a .669" (17mm) diameter for the G3 and Cetme C and variants or our new 1.5" (38.1mm) diameter for m3 grease gun, Sten, Sterling, etc. Machined out of 1018 steel these rails are readily welded and do not require any post weld heat treatment and are machined to MIL-STD-1913 and STANAG 4964 dimensions, providing a secure mount for optics and various other accessories. All rails have a uniform media blasted (white) finish are sealed in plastic and lightly oiled for corrosion protection.