Utility knife blades are designed for use exclusively in slice® Utility Knives. Made of 100% zirconium oxide, these ceramic safety blades retain their sharpness much longer. Because of our proprietary manufacturing and sharpening process, they also feature a finger-friendly edge. Replacement utility blades are non-sparking, non-magnetic and do not need special oil coating or maintenance. slice® donates 1% of sales to Autism research related charities.