Sun umbrella, is mainly used to block the direct sunlight and block the rain umbrella. The sun umbrella can block about 70 UV rays, but can not isolate the reflected UV rays. If there is no UV-coated umbrella, you can also use ordinary sun umbrella, black umbrella defense effect is relatively good, followed by pink, goose yellow, and red almost no anti-ultraviolet function. Large sun umbrella generally refers to non-hand-held umbrella, mainly fixed on the ground. High-quality large sun umbrella should also have anti-ultraviolet, rain and high wind resistance, select the umbrella when the best choice to apply silver cloth umbrella, because the silver layer can reflect the vast majority of ultraviolet light, but also with the rain , Followed by the choice of more compact twill, plain cloth umbrella. Large sun umbrella wind resistance by the main umbrella seat, umbrella column and umbrella to determine the umbrella seat generally have iron pieces, cement, marble and water and other umbrellas. Umbrella column umbrella materials are generally divided into five kinds of wood, iron, aluminum alloy, stainless steel and new composite materials. Wood technology is complex, costly, easy to damage, the market has been rare; at the same time with high strength, no deformation, no rust advantages, a strong resistance to wind, the price is moderate, due to the advantages of material performance size Can do a lot, is to produce the manufacturers are not many, the market is more difficult to buy, to choose such a not afraid of the wind sun umbrella the best. In short, the wood material is easy to damage, the umbrella of the umbrella umbrella cheap, aluminum alloy and stainless steel material of the sun umbrella high price, composite sun umbrella a big wind.