The crystals contained inside your Oasis humidifier act as an important safety mechanism in the event that the humidifier is damaged and protects your instrument from water damage.  That is why its important to keep the correct amount of crystals (.6 cc's) in the humidifier, which is where the OH-4 Humigel replacement kit comes in.  This kit contains enough of the humigel crystals for 5-6 refills, keeping your Oasis humidifier working properly.