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.
Straight razor more feedback on the resistance the blade meets while cutting the hair, which is an indicator of blade sharpness. Hollow-ground blades are preferred by most barbers and some high-end razor manufacturers limit their production exclusively to hollow ground razors. The third and final category refers to blade width. The width of the blade is defined as the distance between the back of the blade and the cutting edge. It is expressed in units of eighth of an inch. The sizes vary from up to , rarely . A wider blade can carry more lather, much like a scoop, during multiple