Nut size Hello, I am interested in ''Pressed Steel Sleeve Coupler'' and ''Forged Girder Coupler - Gravlok'' but I need to know nut size. Please let me know ASAP. With all respect Darius Siaurusevicius Existing Answers These nuts are 7/16ths, you can tighten/loosen them with a regular scaffolding spanner.