The combination square was invented in USA. Our product development team wanted more than just a product. They built features into our Combination Squares. Features like laser-accurate scribing guides, positive indexing at every full inch, a sliding head support and precise, laser-engraved scales. After we had the standard combination square designed, we built the same features into a larger size and two sizes of double squares, too.The feature we think youll find most useful on these squares is the laser-cut scribing guides cut every sixteenth-inch along the blade. The guides are just right size to capture a pencil tip for highly accurate parallel scribing. But wheres the zero point for the scribing guides 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.For years one of our customers favorite features of our fixed-head squares has been the shoulder that keeps the square in position on the edge of your stock. Weve added that to our adjustable squares, too. Just slide the head support out to keep the head of your square perfectly positioned without needing three hands. If its in the way, it just slides back into the head and doesnt interfere with the alignment of the square in any way.The scales engraved on the blades of the squares have 16ths on one edge and 32nds on the other. All scales are laser-engraved to a tolerance of 0.004inch total accumulated error over the entire length of the blade. Thats about the thickness of a human hair spread over the 6-inch, 12-inch or 18-inch blade length. The blades go through a multi-step finishing process to give them a lustrous satin finish, and the deeply engraved graduations are crisp and dark and will never wear off.DIY Supplies: WoodworkingModel Number: GaugesType: A:45 Degree Triangularcolour:Silver+redMaterial:Metal + plasticsize:Total length: about 46.5cmPackage Contents:1 x woodworking caliperOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.