- Silica gel beads are for an air-tight sealed environment.  They continue to absorb moisture until they become fully saturated. They can bring the humidity level down to <10%. - Hanging moisture absorber contains mineral salt named calcium chloride.  These are ideal for small enclosed space like garage, basement, attic, closet, and etc.. Calcium chloride crystals absorb excess moisture in the air. They do not dry air extremely to the point to cause damage to plants, furniture, or any household items. They will slow down when the humidity level is not high and will restart again when necessary. This is cost efficient, because the product will work when it's needed and not when it does not have to. However, calcium chloride is not reusable.