Under Armour

UA Base 4.0 is built for extreme cold weather and lower activity. It uses a unique pattern that's designed to trap heat without adding bulk. Think long underwear, revamped for today's top athletes.

UA Base 4.0 is built for extreme cold weather and lower activity. It uses a unique pattern that's designed to trap heat without adding bulk. Think long underwear, revamped for today's top athletes.

UA Base 4.0 is built for extreme cold weather and lower activity. It uses a unique pattern that's designed to trap heat without adding bulk. Think long underwear, revamped for today's top athletes.

UA Base 4.0 is built for extreme cold weather and lower activity. It uses a unique pattern that's designed to trap heat without adding bulk. Think long underwear, revamped for today's top athletes.

Meet the all-new UA Base—delivering the same trusted warmth without the bulk—now softer and smoother than ever for unmatched comfort on every adventure.

Meet the all-new UA Base—delivering the same trusted warmth without the bulk—now softer and smoother than ever for unmatched comfort on every adventure.

Meet the all-new UA Base—delivering the same trusted warmth without the bulk—now softer and smoother than ever for unmatched comfort on every adventure.

Meet the all-new UA Base—delivering the same trusted warmth without the bulk—now softer and smoother than ever for unmatched comfort on every adventure.

Meet the all-new UA Base—delivering the same trusted warmth without the bulk—now softer and smoother than ever for unmatched comfort on every adventure.

UA Base 3.0 is built for very cold weather and moderate activity. It uses a unique pattern that's designed to trap heat without adding bulk. Think long underwear, revamped for today's top athletes.

UA Base 3.0 is built for very cold weather and moderate activity. It uses a unique pattern that's designed to trap heat without adding bulk. Think long underwear, revamped for today's top athletes.

UA Base 3.0 is built for very cold weather and moderate activity. It uses a unique pattern that's designed to trap heat without adding bulk. Think long underwear, revamped for today's top athletes.