A sheet-metal worker's gauge, made of steel and brass, and graded on one side 6-24. The split between the two pieces of steel gets gradually narrower towards the brass fitting, and the sheet of metal would be placed into the split to ascertain its thickness.

Metal-working in various forms has been an important industry in the Swansea/Neath area, from the earliest copper-smelting and tin works in the Vale of Neath to the steel production undertaken in Port Talbot at the turn of the twenty-first century.