Approaches for desiccant device within an enclosure protecting sensitive electronic equipment. A hard-disk drive (HDD) may comprise a desiccant device that provides a source of a beneficial vapor, such as an antioxidant, a vapor corrosion inhibitor, or a colubricant, within an enclosure of the HDD. The desiccant device absorbs water vapor within the enclosure but does not absorb the beneficial vapor within the enclosure. The desiccant device may comprise a desiccant that has a plurality of micropores within a size range selected so as to allow the absorption of water but exclude the absorption of the beneficial vapor. The desiccant may be, but need not be, within the same physical container as the source of the beneficial vapor.