Photo Etched Pivot Tool for cutting plastic models. Made to fit into handles for Xacto blades and other hobby handles. Blade Thickness .15mm. Markings on each blade indicates the size of the bottom circle. Drill a .5mm hole into model where you want the circle, use that hole as a pivot point to spin the tool. Tool will make circle hole the diameter shown on the tool you use. Sizes: 3.2mm - 4.0mm. This also includes circular metal add-on parts to use in the holes made by this tool.