This hydro-gel jar is a two-way (both active and passive) product. It will maintain 70% humidity with zero chance of over- humidification.  It contains amazing super absorbent polymer crystals, pre-charged for your convenience.  Just remove the lid, exposing the moisture regulation cap, and THE SENTINEL will immediately start keeping watch over your cigars.  There is no guesswork with this jar.  When the gel level decreases to the ADD line, add THE SOLUTION to the FILL line.  Done.

Added benefit:  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!  (4 oz hydro-gel) will humidify up to 200 cigars.