The new GRI DOOR ALERT/ POOL ALARM was designed as an aid for prevention of an unattended access to a pool/ spa area by a small child. Monitoring all doors or windows with CLOSED LOOP magnetic reed switches, the DOOR ALERT/ POOL ALARM will sound an alarm should anyone too small to manage the adult pass through feature attempt access to the pool/ spa area. For maximum protection all moveable openings should be protected in such a manner by the GRI DOOR ALERT/ POOL ALARM. The 289-1, 289-2, 289-3 and 289-4 can be operated with an on-board 9 volt battery with a 12 volt externally supplied DC power source, in which case the battery will perform a back-up function should the externally supplied source fail for any reason. Both power sources have been designed to maintain a minimum sound pressure level of 85db at 10'.