In 1888, the first modern commercial deodorant, Mum, was developed and patented by a U.S. inventor in Philadelphia, Pennsylvania, Edna Murphey. The small company was bought by Bristol-Myers in 1931 and in the late 1940s, Helen Barnett Diserens developed an underarm applicator based on the newly invented ball-point pen. In 1952, the company began marketing the product under the name Ban Roll-On. The product was briefly withdrawn from the market in the U.S., but it is once again available at retailers in the U.S. under the brand Ban. In the UK it is sold under the names Mum Solid and Mum Pump Spray. Chattem acquired Ban deodorant brand in 1998 and subsequently sold it to Kao Corporation in 2000.