I am old enough that I still have wool jerseys. Modern cycling jerseys made with synthetic fibers are just so much better. They are though somewhat expensive and have a limited use as a garment. I mentioned in a previous post that I have been using what are called sun block fishing jerseys which are long sleeved shirts made out of the same material as a cycling jerseys if not a bit thinner. They, unlike wool or cotton they (like a good cycling jersey) dry immediately. I have paid between $8.00 and $15.00 a piece for them on Amazon which is a lot less than I have ever paid for a cycling jersey. Now, I tend to wear them whenever I am out in the sun. At my age I do not need a heavy farmers tan.The point is not whether they block UV rays better than any other material. They do and are cool, comfortable and inexpensive.