X-ACTO X618 100pc X-Life No 18 Heavyweight Chiseling Knife Blades. X-Life Blades are made from the highest quality carbon steel, rigidly tested for hardness, and manufactured to the most stringent specifications. They are oxidized to resist rust and increase durability. Based on independent tests, the X-Life blades show a 30 percent sharper edge and have 54 percent longer life than competitive blades. For deep cross and smooth wood chiseling. Balsa, wood, linoleum, and bass wood. 1/2 inch edge. Packaging may vary. Fits 3/8 inch X-ACTO No 2, Type c, and Type D handles, as well as Excel K2, K5, K6, and K7 Handles.