Secure your offset patio umbrella setup with this 4-piece fillable base plate set designed for cantilever umbrella cross bases (not included). The set forms a 40" x 40" footprint and uses four interlocking plates that connect with metal hooks to help keep the base assembled during use. Each plate includes an easy-fill spout for adding or draining weight, and the built-in grooved handles make it easier to reposition when empty. Depending on your setup needs, the reservoirs can be filled with water, sand, or a sand-and-water mix to add stability. When not in use, the plates stack to a compact 20" x 20" x 10" size for simpler storage. Made from Hdpe, this base set is intended for everyday outdoor use around patios, poolside seating areas, and event spaces, and it pairs well with many 9 to 10 ft offset umbrellas.