Abstract: A generally rectangular housing defines an interior cavity therein. A conventional battery powered alarm circuit is supported within the interior cavity. A supporting suction cup is securable to the housing to permit attachment of the housing to a convenient surface. The housing defines an elongated slot in proximity to the circuit battery and a pair of spring contacts are provided for completing the battery power circuit connection to the alarm circuitry. An insulating tab is receivable within the alarm housing through the slot and extends between one of the spring contacts and its associated battery terminal to interrupt the battery power to the alarm circuit. The insulative tab is coupled to a second suction cup by a flexible line. The alarm system is installed by positioning the alarm housing and the second suction cup on opposite sides of a movable door or window portion.