Glastonbury Southern Gage is known as a leader in the manufacture of thread, variable thread, cylindrical, and spindle gages. Each gage is the finest available because we use only superb quality tool steels, and manufacturing and quality control processes that ensure the best value.  Plug and ring gages are available in a wide range of sizes, in classes Z, Y, X, XX, XXX and a choice of materials to suit your application.