Easily read scale is calibrated for a 1/4-inch router bit Cuts 256 different circles from 2-1/4 to 18-3/16-inches in diameter Circle cutting jig is great for making speaker cutouts -drilled pivot holes keep pins in holes Mounts directly to the base of 19 different models of plunge routers, Weight: 0.63272669194 Pounds, Manufacturer: Jaywool