Usage Tips:est design:Our latest woodworkers edge rule simplifies your life by wrapping around the edge of your stock and giving you an accurate scale on both sides.Just depress the spring-loaded index pin & lock the head at any full inch,now your scribing guides are dialed in and ready for accurate parallel marking. Easy Line Drawing:The blade features the same exclusive saw-tooth design scribing notches found in our Stainless Steel Precision Woodworking Squares. Theres 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. Always Stable:The squares have a firm footing when standing vertical for cabinet checks or machinery adjustment, too. Machined from aircraft grade aluminum, the heads weigh less than the cast iron heads found on other brands of adjustable squares. Two Style for OptionThere are two options. You can choose the angle of 90 degrees or 45 degrees according to your need. Suitable for:It is your ideal choice for DIY and professional work, creating precise lines, angles and precise measurements for engineers, draftsmen and carpenters.