Keep patio umbrellas steady in real outdoor conditions with this 18.5 in square umbrella base weight. Built from durable 900D oxford fabric with an interior Pu coating, the fillable bag set resists tearing, fading, and moisture so it holds up through repeated use on patios, decks, and in gardens. The 2-piece design wraps around umbrella poles and locks in place with fixing buckles, adding stability to offset, cantilever, and center-pole umbrellas alike. Fill each bag with up to 90 lbs of sand, gravel, stones, or soil for a solid counterweight, then empty and fold it flat for compact storage between seasons. Side carry handles and a lightweight 0.8 lb empty weight make it easy to move, fill, and store. Beyond umbrellas, this stabilizer also works well anchoring patio furniture, camping canopies, and market stall setups.