Humidity beads are small silica-gel beads, sold loose, in tubes, or in trays, that are treated to hold a humidor near a set humidity such as 65% or 70%. Silica gel holds water on the surface of its pores, so the beads can take in moisture and release it slowly. Recharge them with distilled water only; PG solution can ruin them. They are generally better at absorbing excess moisture than at releasing it, so they suit humid climates more than very dry ones.
Also called: silica beads, humidor beads