Advanced Intelligence Detects Both Fast Flaming and Slow Smoldering Fires. Artificial Intelligence Techniques Used to Classify Smoke and Fire Profiles. Microprocessor Virtually Eliminates Nuisance Alarms Caused by Everyday Cooking Smoke, Steam, etc. Detection of Polyurethane Foam in both Slow Smoldering and Fast Flaming Fire. Immunity to High-Voltage Current Surges. No Batteries to Change. Maintenance-Free Battery Power Provides 10-Years of Safety Protection. Conforms to New UL Standard 217 8th Edition Requirements.Advanced intelligence detects both fast flaming and slow smoldering firesDetects Both Fast-Flaming And Slow-Smoldering FiresMicroprocessor virtually eliminates nuisance alarms caused by everyday cooking smoke, steam, etc.Detection of polyurethane foam in both slow smoldering and fast flaming firesImmunity to high-voltage current surgesTamper Resistant Design Provides A Higher Level Of SecurityLithium-free 10-year permanent powerAlkaline batteries are safer and more eco-friendlyMaintenance-free battery power provides 10-years of safety protectionTamper-proof design prevents battery removalLED power/status indicatorTest/reset/silence buttonBase dia: 5-5/8 in.