These sand bags are designed to be used with our x-stands for indoor and outdoor displays on a flat level surface. The bag is doughnut-shaped and constructed from durable 600d polyester with a Velcro attachment mechanism and a zipper for adding and removing sand. Once filled with sand, this bag will provide the needed stability so that your x-stand will not blow over in the wind and will remain firm. Sand must be purchased separately from your local hardware store.