Photoelectric
Photoelectric technology is generally more sensitive than ionization technology at detecting large particles, which tend to be produced in greater amounts by smoldering fires, which may smolder for hours before bursting into flame. Sources of these fires may include cigarettes burning in couches or bedding. Each type of detector also comes as AC-operated smoke alarms or battery-operated smoke alarms. Some AC alarms even come with a battery back-up system. Additional options can include an escape light, silencing button, or remote control mute feature.
Look for this symbol on the label: