For those who are home alone, Philips Lifeline offers an emergency lifeline. The company sells personal response systems (PRS) for the elderly and medically at risk who are living independently, and it provides monitoring services from a central facility. Other products include fall detectors and medicine dispensers. Royal Philips Electronics purchased the company, then called Health Watch, for about $750 million in cash in 2007. The acquisition was part of Philips' expansion into the health care market. (It had purchased Lifeline Systems the previous year.) Philips Lifeline monitors some 720,000 elderly or infirm at-home customers in the US and Canada. It charges a monthly fee for its devices.