Helix 180&deg; Shatter Resistant Swing Arm Protractor 6" / 15cm Swing arm protractor rotates 180, helps accurately draw and measure angles. Measure angles from left to right or right to left Easy-to-read inch and centimeter marks. 6" & 10cm ruler integrated at the bottom Made of translucent material to easily see what you are measuring Shatter-resistant material for safety and longer durablility. Beveled edges for easy lift and manipulation. Ideal ages, eight and up Assorted colors (Blue, Teal, & Grey)