Hazardous areas often require the use of optical signals for warning or information purposes. The EExII rotating beacon dSLD 21 offers both of these signalling features. It is designed for continuous operation. If the supply voltage is turned on, the rotating beacon dSLD 21 is activated.The device is available in several versions with various levels of operating voltage and and various signallingcolours. The stable, glass-fibre reinforced polyester (GRP) housing is made to the IP66 degree of protection and may be used indoors or outdoors. The II 2 G EEx de IIC T6 protection class enables the unlimited use of the signalling device in all hazardous areas, zones 1 and 2. The flameproof enclosure and the "increased safety" type of protection of the terminal room guarantee hazardous area protection. The upper part of the flameproof enclosure, which contains the electronic and the mounted halogen lamp, consists of a transparent Makroloncap. An inner cap lends colour to the light. The housing consists completely of GRP. Thus the device is protected against corrosion, and fulfills the requirements of contact safety class II. An equipotentiel bonding is not required. All outer fastening parts are manufactured in non corrosive materials.