This Multipurpose Angle Finder Square Is Extremely Versatile. It Can Be Used For Internal And External Measurements. The Four Pivot Design Makes It Very Flexible. The Angles Are Read From A Protractor Scale. Ideal For Carpentry, Woodworking, And All Types Of Construction.* Plates Are 2.5 X .5 X1" * Comes With 4 Pegs * Tension Screw Is 3" Long * Heavy Duty Construction * Professional Quality