318-18 Features: -Adjustable protractor arm locks into desired position with knurled thumb nut. -Permanently etched graduations from 0 to 180? in opposite directions. -Angle: 180.0 [Max]. -Dial Reading: 0-180-0. Product Type: -Protractors. Generic Dimensions: -Blade Length: 6 in. -Head Length: 3 3/8 in. -Head Width: 2 in. Dimensions: Overall Product Weight: -0.16 Pounds. ROUND HEAD- 3-3/8 x 2 head dimension makes it easier to identify the precise angle MEASURES- Deeply etched graduations read from 0 to 180 in forward and reverse directions and will not wear or rub off ADJUSTABLE- 6 inch adjustable protractor arm locks into desired position with knurled thumb nut to quickly and easily identify angles DURABLE- Stainless steel for precision, strength and rust resistance ESSENTIAL TOOL- Perfect for students, machinists, carpenters and woodworking hobbyists for setting bevels, measuring and transferring angles