XIKAR Crystal Humidifiers use high grade Sodium based Polyacrylamide. It is a plastic material (non-biodegradable & non-toxic) that absorbs and holds up to 450 times its weight in fluid. The gel feels dry to the touch and never ever leaks. It is the perfect medium for humidifiers. A couple of grams of dry gel are enough to fill the crystal humidifiers when fully charged with solution. This creates the ONLY humidifier on the market that is 99.8% void of the available space, less than .2% is occupied by anything other than Propylene Glycol solution, making the humidifiers the most efficient on the market. Store our cigars in a humidor that has a constant 70% humidity. If your humidor holds up to 150 cigars then use this Xikar humidifier jar to regulate its humidity. All you have to do is unscrew the top and place it in your humidor! It will last for 90 days before you need to refill it with Xikar's pre-mixed solution. A slow, steady release of constant Humidity of 70% that lasts up to 90 days before you have to re-fill it. This jar of 2 ounces regulates humidity for up to 150 cigars safely and effectively, and it's very easy to use! Xikar Crystal Humidifier, Lasts Up to 90 Days, Reusable, Crystals Expand, Provides Perfect 70% Humidity, 2 fl oz Jar This product comes with a HUMSOL (Propylene Glycol solution) to fill the jar just unscrew the top, fill it and place in your humidor. HUMSOL Activator and Maintenance Humidor Solution is convenient and easy to use. It is made with the highest food grade propylene glycol and distilled water. It is a 50/50 propylene glycol solution that helps the humidifier automatically stabilize the humidity at an optimum level of 70%. It also actively prevents the formation of mold and bacteria in your humidor. This convenient flip top bottle contains 8 ounces and is a 9 to 12 month supply. Works effectively in all humidification systems and is ideal for activating and maintaining your humidors humidity. The solution should only be applied when setting up your new humidor or when the humidity level suddenly drops. Depending on the temperature and weather, it should be used once every 3 to 6 months. It should not be used more frequently and never exclusively. After activating your humidifier it should only be refilled with pure distilled water until the solution dissipates, at which time it may be used again.