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!
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.