Made from carbon-infused steel for a harder cutting surface that lasts longer. Processed through a unique carburizing heat treatment that actually adds carbon to the metal. Blades hold a razor sharp edge that will endure prolonged use and more sharpening treatments. Each clipper blade is sharpened to exact quality standards. Hand tested before it is shipped. Blades have a Rockwell Hardness rating of 65. Compatible with Andis®, Conair®, Oster® and Wahl® detachable-style clippers.