Big Gator Tools V-DrillGuide Metric and Standard Size Portable Drilling Guide Kit Standard Size: 17 drill sizes, from 1/8" to 3/8", in 1/64" increments Metric Size: 17 drill sizes - 3mm to 9.5mm in 0.5mm increments plus 3.3mm, 4.2mm and 6.8mm Use on flat surfaces, round parts, and corners, Alignment marks on guide to line up on center Non-plated material with light oil coating to prevent rust Special nickel alloyed steel heat treated for durability