Fix the Umbrella Firmly: The umbrella holder can firmly fix the umbrella on the tackle box, protect you and your fishing tools from sunshine or rain even in hot summer days or rainy days. Adjustable tightness: The umbrella mounting bracket has two screw knobs, which can adjust the tightness to fit different sizes of umbrella handles and prevent the umbrella from falling off. Suitable for umbrella handle diameter less than 30mm. Durable material: The adjustable umbrella stand is made of 304 stainless steel, sturdy, anti-deformation, anti-rust and durable, can be used for a long time even in bad weather. Easy Installation: The umbrella stand comes with 2 mounting plates and 8 screws for easy installation and 2 spare screws. There is a slot in the plate for easy mounting the umbrella stand base on the plate. Wide Application: The umbrella stand stand base can apply for fishing fort, fishing fort, fishing tank, the rod fishing rig, the fishing chair, the fishing box, etc. Can be used in the scorching sun or against the winds. Size: Opening 3cm (please see second size chart for specific size)