I stored these in a bag for a long time after purchasing them. I haven't checked the contents. These are the water-filled type, making them convenient to carry. They can be used for various purposes, such as securing awnings, sunshades, and shades, as well as for fixing green curtain nets and as weights for rain protection. This is a set of 4, consisting of 2 bags with 2 pieces each. Please understand that these are used items.