VaporBeads™ are a rechargeable bead system made of medical grade silica which are impregnated with a salt based formula. The beads have micropores for excess moisture absorption to give precise humidity control. Simply dip up to the very first opening (when turned vertically) in distilled or reverse osmosis (RO) water and set in your humidor to maintain a desired relative humidity. Hydration cycles may vary depending upon the container and climate. Normally requires rehydrating every 2-3 weeks. This bead system will maintain a relative humidity of 58% to 65% when saturated.