The Men's Under Armour 2024 Base 3.0 Crew Base Layer is versatile and provides midweight warmth and mobility for various activities. As a midweight base layer shirt, it is best used for winter activities in cold temperatures. With four-way stretch material and sweat-wicking properties, this Under Armour 3.0 base layer provides lasting comfort while the soft, brushed grid interior traps air against your skin.