I prefer to use the Skin Graft blade (SG3) from Swann-Morton (http://www.swann-morton.com/blades3.html). These fit on a standard No.3 scalpel handle and are extremely sharp. I use them for cutting very thin slices of fresh rat kidney and they perform far better than microtome or razor blades. Regards Kevin Randall AstraZeneca Alderley Park UK