Satin chrome blades and protractor heads. Direct reading 0-180° in opposite directions, permitting the direct reading of angles and supplementary angles. Reversible lock bolt allows choice of which graduated side of the blade faces the operator. Protractor heads are made of stable cast iron and finished with a smooth black finish or wrinkle finish. Tempered steel blades with accurate, machine-divided graduations. Reversible. Shoulder on both sides of blade allows tool to be reversed so same angle can be scribed or measured left and right. Spirit level indicates when the base reference surface is level.