3M Corporation, founded in 1929 and based in St. Paul, Minnesota, develops adhesives, abrasives, light management, microreplication, non-woven material, nanotechnology, surface modification, and other products. The company encompasses the Consumer and Office, Display and Graphics, Electro and Communications, Health Care, Industrial and Transportation, and Safety, Security and Protection Services business groups. The firm originally was known for its Scotch (R) pressure-sensitive tapes, introduced in 1925. In the 1950s, the company developed the Thermo-Fax (TM) copying process, Scotchgard (TM) fabric protector, and Scotch-Brite (TM) cleaning pad products. Since the 1960s, it also has developed videotape, carbonless paper, overhead projection machine, medical and dental, pharmaceuticals, radiology, energy control, consumer electronics circuit, filtration system, and other products. The firm introduced its Post-it (R) Notes office products in 1980. The company is a leading supplier of roofing granules, which are used in asphalt shingles. It also is known for the Vikuiti (TM) display enhancement films, which brighten LCD television, computer, cellular telephone, and other displays. 3M Corporation holds 570 patents on its technologies. The company has acquired SCC Products, SoftMed Systems Incorporated, CUNO Incorporated, Pomp Medical and Healthcare Products LLC, and Mahindra Engineering and Chemical Products Limited's cable accessories division. 3M Corporation has offices across the United States. It maintains manufacturing and research operations in over 60 countries. Products are sold in 200 countries. 3M Corporation is listed on the New York Stock Exchange under the MMM symbol. It is one of 30 companies listed on the Dow Jones Industrial Average. It also is listed on the S&P 500 index.