I need sun protection riding 6 to 8 hours a week in the sun. These DeSoto arm cooler do the job and look good at the same time. The fabric traps sweat to create a cooling effect and blocks out the sun.
Doc gave me the side eye on state of sun impact on my arms so picked up these. In So Cal summer heat is your constant companion and these have had no ill affect on my riding. Very comfortable and as advertised even have a cooling effect with sweat. Bonus is if get hit by a fog bank provide some protection from the cold. Sizing chart is tricky if you have road bike weenie biceps but still long arms. But I found they stay in place. I am 6'2" and size large does the trick. They are snug on forearms so this helps. Product info says still need some broad based sun screen cause these don't protect UVB B. All in all my arms are looking the better for these. But not all is lost, still have some cyclist tan on the gap between sleeve and glove!
I've tried about ten brands of these for hot days and the DeSoto remain my favorite for sizing and performance. They don't get as hot when stationary yet they keep me from turning into a lobster.
Best that I've found for humid, triple digit days. Much thinner than the competition, but manage to also be sturdier and stay white when washed with sports wash, something a few other brands haven't done.
Getting to the age where I need to worry about sun spots (I guess that is any age, really) I appreciate good sun sleeves. These are perfect in that you don't really notice them at all. I've used Sugoi and Pearl Izumi sleeves which are fine, but these are better at the same or a better price. I highly recommend.