Universal Security Instruments SS-2895 - 120-Volt AC/DC photoelectric smoke and fire alarm with silence feature and battery drawerPhotoelectric smoke alarms are generally more effective at detecting, slow, smoldering fires--fires which smolder for hours before bursting into flameInterconnect up to 18 units, 12 smoke alarms maximum; when one alarm goes off all units sound their alarm. The alarm also includes an originating alarm feature: when smoke is detected the red LED flashes on the initiating smoke alarmFull-size plastic dust cover protects this smoke alarm form spray applications, dust and other contaminants thereby eliminating the need to remove the alarm during home renovations or constructionThe alarm has a convenient silence feature, which allows you to temporarily override nuisance alarms. This is ideal for cooking fumes and fireplacesThe battery pull-tab allows battery activation without removing the alarm from the mounting bracket--thus reducing installation time