Bambrella's line of umbrella bases are square and shaped and are designed to be heavy duty and durable as well as support all of Bambrella's umbrellas. Size varies from 20 inch to 24 inch and are offered up in choice of Black Granite or bamboo (bamboo base only offered in 24 inch size.) These bases also include stainless steel tube (Stem) for fitting the umbrella pole; insuring the utmost in support and stability. Bambrella umbrella bases add a touch of finished/polished appeal to your umbrella of choice, and this collection also includes a stainless steel deck mount base. All Umbrella bases are backed by the company's 5 year guarantee on base/hardware.