The Moore & Wright MW500-01 Universal 360‚° Bevel Protractor is made from high quality hardened, ground stainless steel, and has a high precision satin chromed scale. It is fitted with a magnifying glass for easy reading with a fine adjustment and height gauge attachment. They have minimum reading time of 5 minutes - this is a visual angle of 5 arc minutes (1 arc min = 1/60 of a degree). Comes with a 300mm (12in) and 150mm (6in) rule and is packed as set in a plastic box.