Potter & Brumfield Inc. (P&B) is the leading manufacturer of electronic relays--devices that control the flow of electric current--in the United States. Vital components in a wide range of products, relays are found in small appliances, automobiles, furnaces and air conditioners, and vending machines. P&B also designs and markets timers, connectors, circuit breakers, input/output modules, and other mechanisms necessary in the transmission of electric power. A subsidiary of the German conglomerate Siemens AG since 1986, P&B focused on developing new products as well as consolidating and automating its production lines in the 1990s, in order to compete more effectively with Japanese relay manufacturers.