Shell-pattern molding across the top gives this square base a finished look rather than a plain slab, and the same HDPE shell resists water, impact and fading. Filled with sand it reaches 22 lbs, with water 33 lbs and with both 44 lbs. A plastic ring and three adapters cover 1.26", 1.34" and 1.5" poles on umbrellas from 6 to 10 ft, and a non-slip underside adds grip on smooth decking. Overall 17.5" x 17.5" x 12", 5.5 lbs empty. Installation is straightforward.