ShelterLogic Canopy Anchor Bag, 4-Pack Constructed with ultra durable polyester fabric Sewn in webbing loop for easy slide through leg connection Innovative dual cylinder design wraps around canopy or shelter leg with sturdy hook and loop fastener strips tightens down fast Industrial grade zipper on top of bag allows wide open access for easy fill with sand or other filler Convenient spike anchor tabs allow for additional temporary anchoring as needed