Our Patented HALF ROUND design has heavy duty materials, just like our other World-Class Umbrella Stand Weight Bags - Ballistic Rip-stop Polyester with triple stitch locked seams, an industry exclusive. Premier Tents Half- Round Umbrella base weight bags are rugged and dependable, and will provide that critical extra protection to guard against tip overs. Half Round umbrellas are fantastic in small spaces, but are known for how easy they tip over - Not Any More! Simply fill the Half-Round weight bag with sand, install over the top of the umbrella stand post, and you are ready to go. Will fit over umbrella posts of up to 3.0" diameter. Our new half-round weight bag design complements the shape of your Half-Round umbrella stand and looks great, all while adding the extra weight needed to keep your umbrella where it should be. See our website for video instructions on the filling and use of your new Gravipod Half-Round Umbrella Stand Weight Bag. NOTE: *Sand and umbrella stand NOT INCLUDED, product volume is approximately 0.50 cu/ft, or one bag of sand from Lowe's or Home Depot. Please keep this in mind when shopping for sand.