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.
Union Metallic Cartridge Company the Crittenden & Tibbals Manufacturing Company of South Coventry, Connecticut, and from C.D. Leet of Springfield, Massachusetts, was moved to Bridgeport where ammunition production began as the Union Metallic Cartridge & Cap Company until the operation was incorporated as Union Metallic Cartridge Company in September 1867. A powder magazine on Success Hill was destroyed by explosion of 16 tons of gunpowder on 14 May 1906. No lives were lost, but damage was reported as far away as Long Island. In February 1909 UMC completed a shot tower which was the tallest building in Connecticut for many years. The red brick