Portable: Patio umbrella holder is lightweight, easy to carry and use, free to change the direction, bring you a more relaxed experience. Bi-folding design: Umbrella clamp adopts bi- folding design, adjustable direction at both ends, flexible and convenient to use. Adjustable: You can adjust the hole diameter by tightening the screws, the maximum clampable thickness is 1-2.6 cm/0.39-1.02 inch, also can be adjusted by the knob in 360 degree direction, with double wave deepening gears, stable and firm. Use scenario: Umbrella holder for chair mounted on chairs, decks, umbrellas, can be used as a fixed outdoor mounting bracket especially meet your basic needs for fishing. Material: Umbrella holder for chair is made of plastic, easy to use, compact and lightweight design with excellent drop and pressure resistance.