1. A gas drying device comprisinga two-piece housing comprising a fixed portion and a detachable portion;
a threaded male connector built into the fixed portion, the threaded male connector having a female restraining nut operable to restrain the fixed portion against the wall of an electric box when the threaded mail connector is inserted into a knockout formed in a wall of the box;
a gasket positioned between the restraining nut and the wall of the box;
a molecular sieve contained within the two-piece housing so that openings in the sieve are open to the ambient atmosphere within the two-piece housing when the housing is closed; and
a volume of desiccant contained within the molecular sieve, wherein at least a portion of the detachable portion comprises a window allowing viewing of the molecular sieve without detaching it from the fixed portion.