From the Manufacturer
The Circle Cutter Attachment is the perfect companion to the Dremel Advantage Rotary Saw. It installs in seconds by depressing the spring loaded slide plate and releasing. This unique slide plate allows your Advantage Rotary Saw to rotate freely eliminating the need to stop and re-grip as you move the tool around the circle. The pivot foot allows you to cut circle diameters from 1-inch up to 19 inches and is ideal for cutting arcs and "S" curves with varying diameter combinations. The precision stamped steel construction assures you accurate cutting with long lasting durability.
Product Description
Advantage Circle Cutter, Attaches To The Dremel Advantage Rotary Saw To Cut Perfect Circles From 1" To 19" Diameter, Ideal For Installing Lighting Fixtures, Plumbing & Many Other Do It Yourself Projects.