Door Contact DC-15 is designed to detect unauthorized opening and closure of doors or windows. Slimmer and shorter than the original design, DC-15 becomes less noticeable and blends naturally into any home décor. DC-15 is tamper-proof against the opening of its enclosure and the removal from its mounting surface. It also alerts the system control unit to any irregular activities and sends low battery signals as well as regular supervision signals to check system integrity. Its built-in extension terminal also allows it to be added to an existing wired sensor to double as a universal transmitter.