My first shave with my new Rockwell 6C. I read that most use #3 or #4 so I used#3. Instead of a new blade I took a Astra SP out of my Gillette Slim. This blade has been used for four shaves. This blade gave three good shaves in a Gillette SuperSpeed then I put in the Slim set at 7 and the face shave was good but I nicked myself three times on the back of my head. I put this blade in the Rockwell and got the best shave with this blade. One of the best shaves I ever had. Tomorrow I'm going for plate #4.