Visol Humidifier with Crystals, 100 to 250 Cigars, Silver Contains Propylene Glycol Crystals (Release Humidity Slowly to Maintain Humidity Balance inside Humidor); Ideal for 100 to 250 Cigar Humidors Saturate the Crystals with Small Amount of Distilled Water and Let the Crystals Absorb and Expand; May Take Up to 3 hours to Soak Completely; Approx. Dimensions: 6.5 inches (Length) x 2.2 inches (Width) x 0.6 inches (Thickness); Approx. Weight: 0.36 pounds Can be Easily Attached to Any Cigar Humidor; Made with Plastic; Reusable, Can Be Used Up 1 to 2 months per Refill Comes Packaged in Cardboard Box; Includes One Large Rectangular Self-Adhesive Magnet for Back of Humidifier