HIGH-QUALITY MATERIAL: This granite umbrella stand tube is made of high-quality industrial grade stainless steel with black paint sprayed on the surface, which is not easy to be corroded and rusted, and is durable. There are welding spots around the bottom of the marble umbrella tube base, which are firmly welded and not easy to bend and break. ADJUSTABLE NOZZLE DIAMETER: Three PVC sleeves are provided in the set. Sizes are 1-1/4"(32mm), 1-1/2"(38mm), 1-9/10"(48mm). Choose the appropriate tube sleeve according to the diameter of the umbrella pole, and then tighten the two on the stone umbrella tube holder Secure the knob so the umbrella pole doesn't wobble even on a windy day. WINDPROOF UMBRELLA STAND: There is a screw hole at the bottom of the table umbrella tube stand base. Insert the supplied screw through the bottom of the granite slate and then through the screw hole at the bottom of the Stainless Steel umbrella tube stand, and then tighten the steel screw to fix the metal tube