NOTIFIER's Fire Sentry SS2, SS3, SS4, FS20X and FS24X flame detectors provides solutions for everything from safe areas to harsh and high risk applications. NOTIFIER's Fire Sentry SS2, SS3, SS4, FS20X and FS24X is a family of multi-spectrum, electro-optical digital fire and flame detectors representing leading edge UV, IR and VIS technology for a wide range of commercial and industrial applications.