I bought two of the Haynes Cool Dri, and two of their X-Temp performance T shirts. I drive a delivery truck in the hot humid Alabama summers and needed something with moisture wicking cool technology. After trying both I prefer the Cool Dri. They are made of a material that is slick and shiny, similar to silk, while the X-Temp fabric feels slightly fuzzy like brushed cotton. For this reason the Cool Dri feels cooler IMO. Both are long enough to stay tucked into jeans or shorts, the sleeves on the Cool Dri are longer for wearing as an outer shirt, while the X-Temp selves are shorter, more suitable as an undershirt. Both wick sweat away and dry quickly, and don't show salt stains like dark cotton.