Check the listing for details. Gentex S Series S Hard Wired Smoke Alarm. Condition: New. Listed at 105.00 USD. The Gentex S photoelectric smoke alarm is engineered to virtually eliminate nuisance alarms and deliver outstanding performance wherever reliable fire protection is required. 9V alkaline battery back-up ensures continued operation even during a power outage. ANSI/UL 217, ANSI/UL 2034 and ANSI/UL 539 listed and warranted for one year from date of purchase. Features:Listed to UL 217, 9th EditionMulti-Criteria smoke sensing including photoelectric light scattering sensing technology 10-year end-of-life indicatorTemporal 3 evacuation signal pattern for smoke and heat annunciation85 dBA evacuation horn piezoHorn frequency 3100HzNominal 2.5% sensitivity8-hour alarm memoryPush button self-test Push button functional test Quick-disconnect wiring harnessInterconnect with Gentex tandem capable smoke alarmsNon-latching (self-restoring) alarmPulsing LED sensing chamberFully insect screenedMounting hardware adapts to standard junction boxesDust cover to prevent contamination during installationLow or missing battery indicator