Simultaneously removes burrs from both sides of sheet metal The DB Handle features a safety guard to protect your hand Unique round cutting blades can be rotated and reversed for longer working life For corners use 1 blade only The range is 0-12mm The standard N80 (BN8010) blades have a 55 degree angle, are made of High Speed Steel, and Hardness 62-64Rc For use on Stainless Steel the Hardened Blades N80M42 (BN8043) are best. Hardness 66-68Rc Blades sold individually, however, we recommend purchasing in multiples of two to ensure even wear and use on the Double Burr