Razor be used on both sides, with two open edges. The blade on the double-edged safety razor is slightly curved to allow for a smoother and cleaner shave. In 1901, the American inventor King Camp Gillette, with the assistance of William Nickerson, patented a new variation of safety razor with disposable blades. Gillette realized that a profit could be made by selling an inexpensive razor with disposable blades. This has been called the razor and blades business model, and has become a very common practice for a wide variety of products. Many other brands of safety razors have come and gone.
Razor early description of a safety razor similar in form to the ones used today is found on William Samuel Henson's 1847 patent application for a comb tooth guard. This guard could be attached to a straight razor or to a razor "the cutting blade which is at right angles with the handle, and resembles somewhat the form of a common hoe." Around 1875 a new design with a smaller blade placed on top of a handle was marketed by the Kampfe Brothers as "the best available shaving method on the market that won’t cut a user, like straight steel razors."