Gravipod 18"x18" Square Umbrella Base Weight Bag-Up to 110#. Safety solution for Patio, Offset and Cantilever Umbrellas. Heavy Duty Ballistic Polyester, XL opening, Weather and UV resistant The Original Umbrella Weight Bag! Simple, convenient, durable and looks great - Just add your own sand* Designed for umbrella stands with up to a 3.0" umbrella post, but can acommodate post sizes of up to 3.5" by filling the bag less full New design - Now includes our exclusive rugged and durable Ballistic Ripstop fabric - no rust, dings or dents Adds up to 110 lbs of weight - soft and easy on the toes, no hard edges to kick. Long lasting and durable - includes a 2 Year Warranty. <span class="a-text-bold">Gravipod</span>GP-18S is designed to fit over your offset, cantilevered or standard patio umbrella stand and provides110 pounds of stabilizing force. <span class="a-text-bold">Easy-Fill System</span> makes it simple to fill with sand in place, so no heavy lifting. <span class="a-text-bold">Quality</span>,durable construction with industry leading components, means no leaking, no tears, and product longevity <span class="a-text-bold">The Original Umbrella Weight</span>has been refined and improved over the years to create the perfect balance of workmanship and performance. <span class="a-text-bold">American ingenuity </span>in design, sales, and support. <span class="a-text-bold">No Hassles.</span> If you&#039;re nothappy, we&#039;re nothappy <span class="a-text-bold">Gravipod - The Original Umbrella Base Weight Bag</span>. Don&#039;t settle for an inferior product. <span class="a-text-bold">Portable Gravity</span> - Holding your stuff to the planet, Period! Place on Stand Fill with Sand Add your Umbrella Industrial Ballistic Rip-Stop Polyester fabric with 5/8 inweave. Top of the line industrial grade fabric. Highest Quality 2&#034; Velcro to prevent messy leakage or spillage, even with multiple fillings. Grade A means it is the strongest, most durable velcro on the market. Triple-stitched 606 Heavy Duty Polyester thread sewn on all seams. The highest tensile strength available for sewing production. Internal water resistant PVC membrane which keeps moisture out and sand inside the product. This critical full additional layer of protection does not degrade.