Dr. RH-PhD Portable Humidation Device 2 oz This Dr. RH PhD hydro-gel jar is a two-way (both active and passive) product so it will maintain 70% humidity with zero chance of over- humidification IF you should have a tobacco beetle in your humidor, it will make a beeline to this jar, burrow into the cap, and not be able to escape. It will be caught in the jar instead of eating your cigars!