A Dessicant Dry Cabinet is an enclosure with a supply of desiccant which maintains an internal environment of 1-50% RH. Desiccant dry cabinets are also called: desiccators, dry boxes, dehumidifying cabinets, and ultra low humidity storage cabinets.

Desiccant itself is defined as: A substance that has a high affinity for water and is used as a drying agent - from the Latin word desiccans. Commercially, desiccant materials are supplied as; Montmorillonite Clay, Silica Gel, Indicating Silica Gel, Molecular Sieve, Calcium Oxide, Calcium Sulfate and Zeolite, just to name a few.

Desiccant naturally 'traps' airborne moisture particles as they come into close proximity. When an amount of desiccant is placed within an enclosure it absorbs as much moisture as it can, making that enclosure dryer. When an item that contains moisture, even trace amounts, is placed within a low humidity ('dry') environment, the moisture will slowly be released from the item into that 'dry' environment. The reality is that the dry cabinet's RH level (relative humidity) is so low that the air inside will act as a magnet to the trapped moisture inside your items, and it will draw it out, into the air within the desiccator. It will continue to do this until there is some kind of equilibrium reached between the moisture level still trapped in the item and moisture level of the desiccator, or until the desiccant is saturated.

Equilibrium, or desiccant saturation, however should never be reached as all desiccant dry cabinets have some manual or automatic procedure for voiding the desiccant of the moisture that it's collected from the cabinet interior and from the items stored within. Once the interior of the desiccator is exposed to refreshed desiccant the dehumidifying, drying, or protective process is continued, and the environment inside the desiccator is maintained.

Typical applications include the prevention and protection against all types of oxidation (rust), the prevention of the growth of fungus on optics, the dry preservation of lab materials and samples as well as the protection of MSDs (moisture sensitive devices) as per IPC/JEDEC J-STD-033C within the electronics industry.