4 piece set Centre head (cast iron) to locate centre of cylinders with Ø 30-100mm Protractor head (cast iron) for measurement of angles 0-180° Square head (cast iron) for 90° and 45° angles Blade made of stainless steel 300mm/12″ with 0.5mm and 1/32′ on front face, 1mm and 1/64′ on back face Marking scribe Levels in both square head and protractor head