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 and balance of the razor. A razor is well balanced if when opened it balances about its pivot pin, indicating that the torques about the pivot point, caused by the corresponding weight distributions of the blade and the handle about the pivot pin, counterbalance each other. A well-balanced razor is both safer to handle when open and easier to shave with. The characteristics of each blade type determine the type of recommended uses for each blade as well as their maintenance routines. Each type has its own strengths and weaknesses depending on the requirements of use. Extra hollow blades such