The Under Armour Boys's Base 2.0 Midweight Long Underwear Top keeps you nice by quickly wicking moisture away from your body and gives you a tailored fit that's not too tight. This crewneck top keeps you warm If you wear it solo for a fall Path run or with a shell and fleece for a day on the slopes. Raglan sleeves and flat-locked seams give you chafe-free comfort as you work or play hard.