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 woodworking scribing gauge is selected from aluminum alloy 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 extended Circles drawing tool makes your operating more , is a good helpers for your work, Manufacturer: OSNIYAW