Our sand bags are constructed from heavy duty 600 denier woven polyester fabric. They are designed in a doughnut-shaped to easily slide around your X-stand (sold separately as 1301849) and provide the needed weight for support and stability in indoor and outdoor applications. A convenient Velcro strap is installed so that the bag can be released for easy installation of the bag around your base. The bag features a sewn-in zipper which can be opened or closed to add sand or prevent the sand from falling out. Please note: Sand is not included.