The reason why the umbrella is so called is nothing more than the effect it has. It can shade the sun and block the rain. It is also often called dual-use umbrella. Now this kind of umbrella is common to us, whether it's sunny in the sun or it's raining heavily.
Some people who know common sense may know that this umbrella is different from those targeted umbrellas. Take the small black umbrella for example, it belongs to the targeted umbrella, which is specially used for sunshade. Although this kind of umbrella is also very good, it can't block the rain. It will not only reduce its service life, but also affect the black glue coating used for sunshade. After the rain wash, it will degumme after a long time, which is very ugly. Although the umbrella has black rubber coating, the materials and workmanship are not the same between them, which leads to different effects. If there is no black glue coating on a sunny umbrella, it is no different from an ordinary umbrella. This kind of black glue is a modern process coating. When the UVA reaches more than 40, it can play a great role in blocking ultraviolet rays. Many umbrellas like this have instructions. It is said that it can block 99% of the ultraviolet rays. Although it's exaggerated, the effect is really obvious through the contrast test with ordinary umbrellas. So no matter how much can be blocked, it's only practical for us.