Construction Material - Steel is the base metal used in the construction of these sets - but not all steel is created equally! Look for steel alloy or, even better, Titanium tipped cutting surfaces. The better the metal the tougher the tap and die so they so they can cut into more Metric/SAE - The size of the tap and die is also important. Metric is of course the European measurement system, SAE are based on US sizes (so use inches instead of millimeters).This is important as you may struggle to use a SAE tap and die set on a vehicle with metric measurements. If the car is made in the US, it probably uses SAE measurements. If it is a European carmaker, it's probably the opposite. If can look for a set with dual Metric and SAE compatibility of course then you don't have t. This item is in the category "Home & Garden\Tools & Workshop Equipment\Hand Tools\Taps & Dies". The seller is "julunita29" and is located in this country: US. This item can be shipped to United States.