Generals heavy duty steel protractors are trusted by machinists and draftsmen worldwide to deliver crucial measurements with unwavering accuracy. The 6 in. adjustable arm is ideal for setting bevels, taking measurements and transferring angles. Ultra-fine etched graduations read from 0 to 180 degrees in forward and reverse directions, and will not wear or rub off. Made of ground stainless steel for precision and durability. Square head protractor. Preferred choice of machinists, draftsmen and mechanics. Used for setting bevels, measuring and transferring angles. 6 in. adjustable protractor arm locks into desired position with knurled thumb nut. Permanently etched graduations from 0 to 180 degrees and from 180 to 0 degrees. Head measures 3-3/8 in. x 2 in. Made of ground stainless steel.