This one-piece rivet gauge tool is designed to help users check rivet length before riveting and inspect the formed shop head after installation. It provides a simple way to verify whether the selected rivet size and final rivet shape are suitable for sheet metal assembly work. The compact one-piece design is easy to keep in a toolbox, workbench, or field kit, making it convenient for aluminum panel work, solid rivet layout, assembly practice, repair tasks, and general metal fabrication projects. A practical measuring accessory for users who need a quick visual reference during riveting work