It works, my arms and hands aren't burned being in the desert sun for hours. I dislike having to put on sunscreen so this is great. Only 2 problems I found within the first few hours of wearing. The seam of the elastic band always irritates my inner bicep. I would use the thumb holes to cover my hand. I left some slack to account for wrist movements but the seam behind the thumb hole tore. The extra threading did stop it and the thumb hole is still in perfect condition, it's just behind the thumb hole that got a tear.