This one revels in the sweat jamborees of hill climbs, ridge runs and desert singletrack under a resolute sun. Made from the fastest-drying of Patagonia's performance baselayer fabrics, it has an open knit that invites airflow and provides excellent wicking and exceptional breathability. When worn beneath layers, it's also insulative enough for chilly days. The self-binding neck is pliable and soft; raglan sleeves and flat-ribbed underarm panels merge out of the way of straps to eliminate chafe. Made of 4-oz 100% polyester (54% recycled)with Gladiodor natural odor control for the garment. Recyclable through the Common Threads Recycling Program.