Big Gator Tools Metric and Standard V Style Hand Tap Guide Kit (MTG500NP, STD500NP) Special nickle plated alloy steel is heat treated. Precision ground base to assure stability and accurate perpendicular alignment on flat surfaces. V-groove on bottom allows for perpendicular alignment with all tap sizes on round parts or corners. Portable, pocket size, A protective plastic storage tube is included for each one Quality 100% Made In the USA