UV-Blocker Chair Umbrella Holder Umbrella Holder: Material - High Strength Plastic, Length - 13 1/2 inches, Inside Diameter - 1 3/4 inch, Large 2 1/2 inch Thumb Screw, Light Weight 13.2 oz. Clamp Mount: Color  Black, Material - Powder Coated Marine Grade Aluminum, Ball Size 1 1/2 inch Quick secure installation. Lifetime Warranty! Made in U.S.A.