The Columbia Zero Rules is a lightweight, comfortable short-sleeve tee with excellent thermoregulation. With its Omni-Freeze ZERO™ technology, this shirt senses perspiration and lowers the temperature of the fabric, for a permanently cool feel. In addition, its Omni-Wick™ system wicks perspiration to the outer layers of the shirt, accelerating evaporation. Designed for hiking and trekking, this shirt keeps you cool even on multi-day outings Features: Composition: 100% PolyesterOmni-Freeze ZERO™: Thermoregulating technology activated upon contact with perspirationOmni-wick™ technology for advanced moisture dispersion and accelerated evaporationZinc pyrithione antimicrobial treatmentComfortable, stretchy fabricBack height: 68.5cm Hiking tee-shirt Columbia ---M's Zero Rules SS Shirt Cloudburst