ProtecPro Dehumidifying Tablets use a drying agent known as a desiccant. You put the desiccant in a microwave or conventional oven to heat up. Then let it cool a little. Then place the desiccant in the jar and the hearing aids on top of it. Close the lid on the jar and leave the aids in it overnight. The desiccant lasts approx. 3 months if used daily.