One shell does three jobs here: it weighs down a patio umbrella, holds a 21-in tray as a garden end table, and becomes a planter box once that tray lifts away. The bag inside fills with 175 lb of sand or 14.5 gal of water, so the empty 21-lb base is easy to carry out and heavy once it settles. Two hand-turn knobs clamp the pole and the tray, two adapters step the socket down for 1.5-in and 1.9-in poles, and a pair of wheels with grab handles let the filled base roll across a deck. Molded HDPE panels carry reinforcing grooves, and a bottom drain hole releases rain from the soil. Color: Black; Material: HDPE Metal; Overall Dimensions: 21" x 21" x 17.5" (L x W x H); Interior Size: 17.5" x 18" x 9.5" (L x W x H); Pole Diameter: 1.5"/1.9" Suitable Patio Umbrella; Capacity of the Sand: 175 lbs Fill; Net Weight: 21 lbs; Box Qty: 1(May vary by batch); Package Includes: 1 x Umbrella Base 1 x Table Tray; 1 x Weighted Bag 1 x User's Manual; Size of the Planter Box: 21" x 21" x 12"(L x W x H); Size of the Table Tray: 21" x 21" (L x W)