Non-Indicating Drierite is anhydrous calcium sulfate. It is of neutral pH, constant in volume, chemically inert except toward water, insoluble in organic liquids and refrigerants, non-disintegrating, non-wetting, non-toxic, non-corrosive, non-channeling, generally recognized as safe (GRAS) by the FDA, not regulated by OSHA, economical to use, and can be regenerated repeatedly for reuse. Typical analysis >99.5% CaS04.