Dri-Can is a small, perforated metal canister that measures (2" x 4" x 1/2") packed with approx. 42 grams (1.5 oz.) of blue indicating silica gel. The desiccant material within the canister attracts water vapor, condenses it, and holds it. A "window" in the center of the canister allows you to see when the blue indicating silica gel turns pink once fully saturated indicating regeneration is needed. Once it has absorbed all the moisture it can hold, it can be regenerated easily with a simple heat treatment in an oven. Cooling of the heated silica gel must be done in a humidity controlled environment so as not to reabsorb unwanted moisture until needed. One Dri-Can will maintain a constant level of humidity within a sealed space of approx. three cubic feet. Sold by the each.