All you have to do is to remove the screws, fix the woodworking Compasses, then adjust the size, You can adjust the of the Circles as needed to meet various drawing needs, so that you can save your time for consolidation and assembly The scale of woodworking Compasses Scriber is printed by professional, the markings are clear and easy to read with the white on the redness background, making it easy to draw circles of various sizes The extended Circles drawing tool makes your operating more, is a good for your work Circles marking tool is 36.5mm, and the Circles is 300mm, the Circles of extended scribing Circles ruler is 550mm Adjustable size, you can measure or draw different sizes of the Arcs and circles as your need The woodworking scribing gauge is selected from aluminum alloy, Manufacturer: YUGSHNKFC