When winter brings on the chill, fight back with The Under Armour Youth UA Base 2.0 Midweight Long Sleeve Crew. The unique negative grid traps monster warmth without adding weight, and it's smooth on the outside to let you layer. UA Base 2.0 is the most versatile of the UA Base thermals, built for basically anything you do outside. Constructed of 93% polyester, 7% elastane fabric. UA Base 2.0 is highly versatile mid weight protection for colder conditions and a variety of activity levels. Soft, brushed negative grid interior traps hot air, providing superior warmth. Four way stretch fabrication allows greater mobility and maintains shape. Signature Moisture Transport System wicks sweat away from the body. Quick dry fabrication keeps you light and comfortable. ArmourBlock anti odor technology prevents the growth of odor causing microbes. Raglan sleeve construction and flatlock stitching allow a full range of motion without chafing. Fitted sits close to the skin for a streamlined fit without the squeeze of compression. Import.