Square Metric Ruler for Metalsmiths and Jewelers, Stainless Steel, 90°

A stainless steel try square built at a fixed 90 degree angle, with metric markings down one arm for measuring as you check the angle. It's sized for bench work, not construction, small enough to sit in a jeweler's tool roll next to pliers and files. Stainless means it won't react with metal filings or pick up rust from sweat and handling.

This is the tool that tells you a corner is actually square before you solder it, not after. Jewelers and metalsmiths use it constantly and invisibly, checking a bezel or a box joint is true before committing heat to it. A cheap square drifts a few degrees over time; a good one doesn't, which is the whole reason to own one instead of eyeballing it.