4.5-pound 2.0kg or 2,000gm moisture absorbing container bag with hookcontents: 80-percent clay desiccant/20-percent caci2 calcium chloridethese bags are made of sewn polyester non-woven with strong plastic hook that can be easily be hung from the inside of container, closet, garage, basement, etc. Protect your cargo against -inchcontainer rain-inch and other moisture problems during shipment including mildew, mold and corrosion.about 10 bags per 20' container and 20 bags per 40' container. Usage can vary depending on your application, conditions, length of storage, etc.