Swing Arm Protractor, Includes Easy To Read Inches & Centimeter Marks For Measuring Arcs, Swing Arm Provides A Straight Edge That Ensures Precise Measurement & Makes Drawing Perfect Angles A Breeze, Easy To Read Inches & Centimeter, Made From Heavy Duty Shatter Resistant Plastic To Resist Bending & Shattering, Ideal For Kids Ages 8 & Up, Lifetime Warranty.