Andis® UltraEdge™ Blades are made from carbon-infused steel for a harder cutting surface that lasts longer. Size 3/4 HT Blade has a 3/4" blade cut.Andis® UltraEdge™ blades are made from high-carbon steel and processed through a unique carburizing heat treatment that actually adds carbon to the metal. More carbon on the metal means a harder cutting surface. These dog cutter blades hold a razor sharp edge that will endure prolonged use and more sharpening treatments. Each Andis UltraEdge blade is sharpened to exact quality standards Hand-tested before it is shipped Blades have a Rockwell Hardness rating of 65