The secret to the Posi-Lock T-Square is the series of precisely machined indexing holes and the spring-loaded, tight-tolerance indexing pin that meshes with them. The pin snaps into place giving you the confidence to know it is spot-on accurate. Even when you’re not working with angles, this is a lay out tool you’ll reach for on almost every project. The blade features the same exclusive “saw-tooth” design scribing notches found in our new Stainless Steel Precision Woodworking Squares. There’s a notch every sixteenth-inch all along the blade. Just drop your pencil in the notch and slide the head along the edge of your stock for a perfectly parallel line. The Posi-Lock T-Square also functions as a hook rule, giving you a positive reference from the edge of your stock. Both edges of the blade are laser engraved with an inch scale in 1/32” increments. The graduations are held to a tolerance of ±.004" total accumulated error over the length of the blade. The thin, satin-finish stainless-steel blade is easy to read and minimizes parallax error.