Oster CryogenX Detachable Pet Clipper Blade, Size 5F (078919-176-005) Oster Cryogen-X blades are made using a 12 step process that ensures superior Cutting quality Leaves hair 1/4 inch in length. Patented Cryogen-X process take the blade to -300 degree F for extra hardness Hand lapped for a smooth cut finish Handcrafted in the USA