I was specting for a magic high tech garment, to keep me cool under an all day long exposition to summer sun, but I just was unable to stand it for more than an hour. I'm not saying that I wasn't protected against UV harmful rays, but it was absolutly unconfortable to feel the sinthetic material on my skin, sweating a lot. Just to be fair, the experience with a similar Columbia stuff was also as desappointing. I think they are designed to be worn in wintertime, whe you look for being under the sun to get some warmness...