Parallel Accuracy: Our latest precision ruler can ensure unparalleled accuracy in panel layout operation. Simply press your head at the desired angle and then press straight line. The head can be adjusted from 0 to 70 and is firmly locked every 5 (plus 22-1/2 and 67-1/2), to ensure you the exact reference angle and length accordingly. Joinery edge principle: TTKJ t-square's secret is a series of precision-machined indexing and spring holes, a long-tolerance indexing pin that connects to them. The pin snaps into place, giving you confidence that it is accurate. Three sizes available: it is 10 inch, 15 inch or 20 inch. Both edges of the blade are laser engraved with an inch scale in 1/32? Steps.Graduations are kept to tolerance. 004" total cumulative error on blade length. The thin, satin stainless steel blade is easy to read and minimizes parallax error. Excellent wood stacking tools: Even if you're not working at an angle, this is a wood stacker that can reach almost any project. The blade has the same exclusive saw tooth Design dies found in our new precision stainless steel woodworking squares. There is a notch every sixteenth inch along the blade. Simply drop the pencil into the cutout and move your head along the edge of the magazine to create a perfectly parallel line. Material: Metal Color: Silver Size: 10 inch, 15 inch, 20 inch Weight: About 300g, 320g, 350g Measuring Range: 0-70 Degree Measuring Accuracy: 1mm Type: Angle RulerPackage Included1 * Carpenters Edge Rule