Smoke alarm efficiently utilizes both ionization and photoelectric smoke sensors to detect both flaming and smoldering fires in their earliest stages. Contains a single test/silence button, alarm source indicator with an alarm and power test feature. Specially designed with a vortex turret construction ensuring optimal smoke entry. Delivers a sound level of 85 db at 10 feet and operates at 40 to 100 degrees Fahrenheit. Powered by a 9 volt alkaline battery backup and measures 5.25 inch diameter x 2.2 inch width. Can conveniently be interconnected with up to 18 units. Product includes tamper resistant “lock-it” key mounting hardware and 10 year limited warranty.