Hydra Shade’s umbrella design allows wind venting without loss of sun protection. It is constructed of marine quality stainless steel and lightweight aluminum. It is a rust free frame with a mildew & fade resistant nylon umbrella that is a reflective to the sun’s harmful UV rays and is rated over UPF 30. Hydra Shade is designed for use with any cylinder or rod holder opening, and offers a tilt and telescoping height adjustment. It is made to stay in place and remain in the cylinder by expanding the umbrella base. There are endless custom applications in which a Hydra Shade can be adapted to your boating lifestyle. Additional tie downs are NOT necessary with the Hydra Shade boat umbrella. You can use a Hydra Shade on a Kayak, Sailboat, Sportifsh Convertible, Center console, bass boat, lake boats, deck boat, powerboat, paddle boats, even a dingy. Then when you arrive at a beach or sand bar, switch to the beach spike and you are all set with a telescoping beach umbrella.