If diamonds are forever, it only stands to reason that a diamond-clad razor blade will last far longer than conventional steel ones. The Diamaze PSD, a feat of German engineering, is composed of a tungsten carbide blade that is coated with a film of synthetic, industrial-grade diamonds. Sharpened to produce a cutting edge of only a few nanometers, the blade is said to last 1,000 times longer than regular blades, meaning it stays sharp for years, rather than weeks.