California Home Spas SHBUBBL Black Basic Umbrella Base. Durable and versatile, the 30lb. Umbrella Base is crafted from fiberglass reinforced cast concrete. The base 30 lb. Umbrella Basse is designed to fit umbrella poles up to 1.5″ in diameter and includes a set screw to ensure your umbrella remains secure within your outdoor space. The SHaDE 30lb. Umbrella Base is recommended for use with table mounted umbrellas.