NT offers 2 models of heavy duty circle cutter. One with sturdy aluminum die-cast body and non-slip rubber grip for extra stability. Circle can range from 1-3/16" ~ 10-1/4" diameter and great for making pipe holes in carpet, rounding corners, etc. Another, large circle cutter, to cut larger circles, with sturdy aluminum beam and rotating grip. Circles range from 3-15/16" ~ 39-3/8" diameter. Both are great carpentry tool and ideal to cut floor sheets, carpet and thin veneer, etc. for your diy projects and drywall, roofing or flooring construction jobs. Professional blades used for these NT heavy duty circle cutters are made of high quality carbon tool steel and produced through multiple stages of precise process to obtain the ultimate sharpness and optimum edge-retention. Made in Japan.