The G.R.I. 290 Series Door Monitors have been designed to monitor access points leading to or from a controlled area, thus preventing doors from being accidentally left open or purposely propped open for extended periods of time. The 290 Series Door Monitors are fully self-contained alarm systems that can be mounted locally or remotely to monitor an access door using a simple closed loop magnetic reed switch. A perfect solution for that single exit door at the end of a long hallway or that isolated doorway everyone seems to forget about