This 17.5" heavy-duty round umbrella base is ideal for holding your beloved umbrella to beautify your surrounding environment. This is our 17.5" square umbrella base, which is ideal for holding your umbrella securely and evenly in place. It is a really practical addition to your backyard or your patio area. Includes a coupler to allow it to fit 38mm to 48mm (by removing the adapter) in diameter umbrella poles. Includes a hand-turn knob for securing the umbrella to the base. Don't hesitate to