This DRIERITE Disposable Desiccant Cartridge (Stock No. 40451) dries displacement air entering storage drums to -100° F dewpoint. It prevents condensation of water vapor and resulting contamination in A Side Drums of the SPF Rig. The indicator window turns from blue to pink when the cartridge is exhausted. Mounting Bung Drum Adaptor Sold Separately. Condensation or absorption of water vapor by a material in a storage vessel can be prevented by the installation of one of these drying columns in the vent piping. When the material in a storage vessel is removed, the moisture laden air replacing the material is completely dried by the desiccant column in the vent line. Breathing through the vent line occurs daily from changes in atmospheric pressure and temperature. These DRIERITE units will prevent contamination from this source. These driers will protect storage vessels up to 400,000 gallons. The drying units will produce dry air (-100° F dewpoint) for flow rates up to 1200 gallons per minute (160 cfm). The moisture indicator eliminates guesswork; it tells you when the DRIERITE is exhausted. The glass window has a few ounces of Indicating DRIERITE behind it. The Indicating DRIERITE turns from blue to pink when the drier is exhausted. The drier contains the highly efficient Du-Cal DRIERITE.