Applies to ISO metric screw threads having the basic profile as defined in DIN 13 Part 19. The limits for the bolt root radius are expressed by R = 0.144P = H/6 for the maximum dimensions and by Rmin = 0,125 P = H/7 for the minimum dimension of the minor diameter d3, as specified in DIN 13 Part 14. It specifies selected sizes for coarse and fine screw threads for screws, bolts and nuts and limits of sizes for commonly used tolerance classes.