The Terramar Body Sensors Men's Helix Mountain Long Sleeve Tee is the perfect shirt for cooler weather workouts or when more sun protection is needed. Powered by Terramar's unique ec2 Qwik Dri thermoregulating technology, the Helix fabric is lightweight, moisture wicking, and breathable ideal for travel, trail running, working out, and cross training. Works great on its own or as a baselayer. Constructed of 100% micro polyester fabric. ec2 Qwik Dri Thermoregulation Comfort Technology. Lightweight temperature control layer prevents moisture buildup during intense workouts. Designed to create air pockets for improved insulation and moisture transport. Soft, breathable, and fast drying. 2 sided, knit all flat seam construction for comfort and durability non chafing next to skin. Tagless for extra comfort. Fabric provides UPF 25 sun protection, shielding skin from harmful ultraviolet rays. Anti microbial treatment for odor prevention. Warmth Factor 1.0. Import.