FEATURES * Compact size offers maximum protection with oversize trim plate to cover marks left by standard size detectors. * More visually appealing than larger, bulkier units. * Flashing red light indicates alarm is receiving power. * Ionization chamber responds fast to low-smoke flaming fires. * Unit will sound a warning chirp when battery is low. * Test button check horn, battery and alarm circuitry. * Loud piercing, pulsating horn. * Special twist-off mounting bracket for fast installation and safe battery replacement. * 9 volt battery included. * UL listed