This sock definitely feels a different than your favorite wool pair. I don't find it unpleasant in any way. I have ridden with this sock in 30 degree weather in my Shimano boots and only toward the end of the ride felt anything like cold toes. I should ride with one Castelli wool on one foot and this sock on the other. Maybe you will try that when you buy a pair? In the meantime, what the hell are we going to do with all the plastic you see along the side of the road? This is another way we are screwing up the planet we want to ride on. Castelli has my respect for doing something good for Mother Earth!
Look you put on sun screen but after an hour where is it? I don't know but not on your arms. The Procorsa Sun Sleeves are a slightly heavier feeling fabric the Castelli sun sleeves but fit feel and protect your arms every bit as well. Put them on before you out on your jersey and they seem to stay up better. Otherwise, there can be a gap between jersey and the sleeve which looks not pro and can be annoying to pull them up while riding. I also use them hiking, doing yard work and occasional fishing trip.
When the heat index is between 90-100 degrees you may not think of adding another layer until you try this base layer. Then you look for it each and every hot weather ride. This micro thin layer absorbs sweat and then the convection cooling that keeps your core temperature down is enhanced. I now have two of them even though they quickly dry after hand washing to get the salt off. I also bought them for my hiking wife. I am 5 feet nine inches tall and between 160 pounds. A medium size fits just
If, like me, you aren't waiting for the "perfect" weather to ride you'll be surprised to find yourself ordering this 'base layer' again after using it on a 90-degree day. This base layer is a micro thin sweat wicking layer that allows your body to keep your core temperature lower. While it doesn't replace drinking massive amounts of fluid when the heat index is over a hundred degrees every little bit helps. I am 5'9' inches , 164 pounds and wear medium. My 5' 1"' wife who hikes a lot has two in size small. If you ride frequently having a second set is nice though I have hand washed mine and they dry almost instantly.