ETA hand2mind Clear, Plastic, Student Math Protractor Set for Classroom (Pack of 20) The classic math angle measurement tool is available in class-sized quantities The clear plastic design allows visibility below, and the black markings make it easy to read The scale has 1 degree graduations up to 180 degrees Each protractor measures 6-inches across the base, and 10cm along the inside cut-out Includes 20 transparent plastic protractors