6" Adjustable Steel Protractor, Preferred By Machinists, Draftspeople, & Mechanics For Setting Bevels, Measuring & Transferring Angles, Made Of Ground Stainless Steel For Optimum Accuracy, Permanently Etched Graduations From 0 To 190 Degree In Opposite Directions, 3-3/8" x 2" Square Are Head, 6" Adjustable Protractor Arm Locks Into Desired Position With Knurled Thumb Nut.