Gas Purged—a controlled flow of clean, dry process gas (usually nitrogen) dilutes ambient, moisture-laden air, which gradually exits through a bleed valve. Available monitor/control systems regulate chamber humidity, temperature, particles, and/or oxygen levels to maintain programmable set point values.
Desiccant—adsorbs moisture from air inside the glovebox. The desiccant is most often indicating silica gel or molecular sieve, but in critical applications catalytic desiccants are use to scavenge minute amounts of oxygen or water vapor.
None—uncontrolled cabinets provide a dust-free environment without RH control, or include ventilation ports for fume containment.