MATERIAL: Made of sturdy iron, strong to hold up the umbrella. The galvanized surface makes the umbrella clamp have a strong oxidation resistance and not easy to rust. SIZE: Fits the umbrella pole of 0-1.5 inches diameter, the max clampable thickness is 1.97 inches (Please measure deck thickness and umbrella pole diameter to check if it fits before order). MAXIMIZING SPACE: The clamp-on design saves a lot of floor space on deck and keep the deck neat. EASY TO SET UP: The umbrella holder clamps and tightens easily to the railing, can quickly move it from place to place without the need for tools. Comes with a rubber cover over tightening bolt to protect your rail and make the umbrella stand more stable for use. PERFECT FOR: Bench, bleachers, deck railing, patio, pool, balcony, picnic table, fence, beach seat, add lots of shade with the umbrella. Specifications: Material: Iron. Size: Fits the umbrella pole of 0-1.5 inches diameter. Max Clampable Thickness: 1.97 inches. Package Includes:1 Umbrella Clamp..