Single layers can have a bigger impact than you think. The women's Mountain Hardwear AirMesh half-zip pullover's lightweight mesh/fleece fabric absorbs sweat, dries quickly and insulates in the cold.
Features
Fabric features tubular interior fibers to regulate temperature, all while reducing weight by half compared to yarns of similar thickness
Sleek mesh exterior won't bind when worn beneath a shell or additional mid layer; brushed microfleece interior traps air for warmth
Stand-up collar with center-front half-length zipper allows for quick and effective ventilation
Side seams are designed to prevent chafing
Raglan sleeves provide excellent freedom of movement
Low-profile thumbholes keep sleeves in place and provide hand warmth