This grey closing plate is a separate component of the range of control and signaling units, Harmony 9001K / 9001SK diameter 30mm. It can be is easiliy plugged in a diameter 30mm empty hole. The 30 mm Harmony range offers a large choice of robust and reliable products to meet a great number of applications in heavy industries such as petrochemy, metallurgy, mining oil and gas wastewater treatment, automobile manufacturing. It is UL listed and CSA certified, CE declaration of conformity and RoHS compliant.