Built with nature&&';;s most advanced performance fibers. The Aire Long Sleeve blends alpaca fiber with eucalyptus-based Tencel (TM) for breathable, thermoregulating comfort that works year-round. Ultralight yet strong, it keeps you cool in warm weather, adds light warmth when it&&';;s cool, and dries quickly without the synthetic feel. Naturally resists odor so you can wear it more and wash it less. Designed with a slim fit, added length, and a refined finish, it&&';;s a smarter, more natural layer for any season. Why you&';ll love this Softest long sleeve shirt you&&';;ll ever own Moisture wicking and odor resistant Flexible and naturally thermoregulating Fully machine-washable :) For Hiking, Climbing, Camping, Travel Material 85% Tencel / 15% Royal Alpaca Fit & Feel Slim / Long Classic