This is a sharper blade than the Cosmeau Green Sharpness 1 for more advanced users of safety razors. An increase in sharpness will give you a better and closer shave but may increase the risk of cuts. So we recommend our sharpest blades only to the more advanced safety razor users. Cosmeau safety razor blades is specially designed for women's skin and all parts of the body. Thus, the sharpness is tuned to be effective over different body parts with different hair thickness. They are excellent all-round blades and sharpness 3 is suitable for advanced users. The blade is high quality Swedish steel. A sharper blade cuts through thicker hair more easily such as in the armpits.