The Andis Pet US-1 Replacement Blade Set is the best for cutting performance on US-1 model clippers. The blades are made of carbon steel for long life and fit Oster A5 and Wahl KM Series. It's a perfect replacement Blade for our ENVY Clipper and leaves Hair 1/50" (0.5 mm) to 3/32" (2.4 mm). Ensure the longevity of your blade's life by oiling it before every use.