Oster Cryogen Blades are produced from the finest high-carbon steel and handcrafted to rigorous standards, providing unparalleled precision and performance. Each American-made blade is hardened to RC62-66 (Rockwell Scale C) before receiving a cryogenic treatment to further enhance the hardening process. Oster’s patented Cryogen-X™ process takes the blades down to -300 degrees for a deep freeze, producing a harder, sharper blade which extends the product life. Each blade is then hand lapped for a smooth cut finish. The 40 blade leaves hair 1/100 in making it ideal for veterinary surgical prep. Compatible with all Oster universal comb attachments and all Oster clippers except the Clipmaster. Clipper blade Made from high-carbon steel American-made Hardened to RC62-66 Patented Cryogen-X™ process Harder, sharper blade Long lasting Hand lapped for smooth cutting finish Ideal for veterinary surgical prep Leaves hair 1/100 in Compatible with all Oster universal comb attachments Fits all Oster clippers (excluding the Clipmaster)