10-lb. refill crystals for DRI-Z-AIR Dehumidifiers. Non-toxic, septic safe. DRI-Z-AIR removes moisture from the interiors of trailers, campers, and boats during periods of storage and lay-up. Keeps moisture from clothes, sheets, shoes etc. Helps to prevent condensation and keeps mold and mildew from forming on your windows, walls and ceilings during storage. DRI-Z-AIR unit not included.