The weight of your umbrella base is determined by the size of your umbrella canopy. Slim profile base should only be used when an umbrella is paired with a dining table. For a freestanding umbrella (in other words, not in a table), you will need a 50 lb. base for a 7-1/2 ft. or 9 ft. umbrella and a 100 lb.+ base for an 11 ft. umbrella.