Robert P.wrote a review of Castelli Core Mesh Short Sleeve Base Layer on July 29, 2010
This base layer is perhaps the best warm weather base layer I have ever used. It is made of a very fine polyester that is so light and soft you would swear it is cotton. But the similarities to cotton stop there as this garment performs far better. This base layer does what it is designed to do, keep you cool and dry, without you ever even realizing it is there. Once you put it on, you totally forget about it as it simply disappears. It is cut true to size and fits snug against the body so it wicks sweat away quickly and efficiently. It dries extremely quickly too.
I live in south Florida where it is exteremely hot and humid even in the early mornings. This base layer keeps me cool and comfortble for my entire 40 mile morning ride. In the hot weather I use it by itself for my training rides and in cooler weather I use it under my jersey. This is a truely outstanding garment that should be in every cyclist's closet. I own 4 and plan to buy more.