This umbrella base weight bag is made from extra durable 600D ripstop polyester with triple stitched locked seams. It measures 18" in diameter with a 2.75" diameter center hole to fit most umbrella bases. Fill with sand and insert on top of an existing base for added stability of your patio umbrella. Base and sand not inlcuded. The zippered side pocket make for easy filling. By Trademark Innovations.