1、ADJUSTABLE ANGLE MARKER: By moving and rotating the T square ruler adjustable angle indicator to set any angle from 0° to 180°, you can improve accuracy and save measurement time 2、DURABLE ALUMINUM ALLOY: Crafting T square ruler is made of anodized aluminum alloy processed by CNC, which is rust proof, durable, corrosively resistant, with a smooth surface and will not hurt hands 3、CLEAR SCALE: The scale lines of the carpenter work ruler are laser printed, and the easy to read scale is bright and white on a red design 4、ACCURATE DESIGN: The T square ruler feature an ergonomic design that reduce stress on the elbow or wrist. The edge is machined at a 25 degree bevel angle, and the bevel design reduce parallax and improve measurement and marking accuracy 5、MAIN PURPOSE: T square ruler protractor angle finder is used for line drawing, measurement, support 0~90° parallel, vertical marking