Circles marking tool radius is 36.5mm, and the Circles radius is 300mm,the Circles radius of extended scribing Circles ruler is 550mm. Adjustable radius size, you can measure or draw different sizes of the Arcs and circles as your need. All you have to do is to remove the screws, fix the woodworking Compasses, then adjust the radius size, You can adjust the radius of the Circles as needed to meet various drawing needs, so that you can save your time for consolidation and assembly. The extended Circles drawing tool makes your operating more convenient, is a good helpers for your work. 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 easy to draw circles of various sizes. The woodworking scribing gauge is selected from aluminum alloy, Manufacturer: TWEW