Boveda 62% & 58% Humidity Packs - (12, 20, 100 Count | 67 Gram)Boveda's patented 2 way humidity control continually responds to ambient conditions by adding or removing moisture to affect the enclosed environment and deliver the pre determined relative humidity (RH) level printed on the pack. Its well known in science that certain salts mixed with water will naturally regulate humidity. We just patented the way that made it practical for packaging. Other packaging inserts either add moisture or remove moisture.