Razor blades are constructed from a specific corrosion-resistant steel mix known as carbide steel, which is created from a tungsten-carbon alloy. Razor blades that are over 20 times larger and many times thicker than modern ones are still used today in certain specialized applications such as meat grinding. The first mass-produced razor blade was invented by George de Mohrenschildt in 1879. He called his invention "blades for shaving the dead," because at this time most people had their hair cut by barbers who used knives to shave off individual hairs. De Mohrenschildt's razor blades were actually round pieces of metal sheeting that were attached to each other with small pins. It wasn't until about 100 years later that manufacturers started producing razor blades that were actually designed to be used multiple times. The first one of these new designs came from Germany where it is now considered tradition to give Christmas gifts called "razor calendars" that feature photographs of people using different objects as razor handles. These include a chair back, a door handle, and even a pair of scissors. Since then, almost every major brand of razor has released its own version of this type of calendar. They all share similar features including a plastic or cardboard cover containing 12 pages that display one image each day from December 1 to December 31.