Big Gator Tools MTG500NP V-Tap Guide Universal & portable V-Tap guide provides perpendicular alignment of ground thread taps on flat, round & square cornered materials 9 guide holes cover 13 metric ground thread tap sizes: 1.6mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm Heat-treated nickel alloy steel provides durability & accuracy Precision ground base provides perpendicular alignment of tap on flat material V-Groove aligns tap on round and square cornered materials