The HAZARD-GARD™ EXS and EXDS series explosion-proof strobe lights are designed for installation indoors and outdoors in locations which are hazardous due to the presence of flammable vapors or gases, ignitable dusts or ignitable fibers and flying's. The units are UL listed for Type 3R and 4X installations. The 120 V and 24 VDC models are marine rated. The strobes are available for pendant, wall, stanchion and ceiling mounts and come in six different globe colors. The EXDS series is diode polarized for use in electrically supervised circuits. Electrically supervised circuits are typically used in life-safety or security applications. Under normal operation the diode is reversed biased, meaning it blocks voltage from being applied to the strobe and prevents it from lighting. When an initiating device such as a smoke detector is activated, the diode's polarity is reversed through a circuit panel. The diode becomes forward biased, allowing voltage to the device and activating the strobe.