From morning's first frosty steps to midday sweat and exhilaration, the men's REI Co-op lightweight base layer bottoms wick and breathe to keep you comfortable all the way.

• Made of a soft, snag-resistant polyester blend that wicks sweat and dries fast to keep you warm in winter and cool as the season turns to spring
• Spandex in the fabric provides 4-way stretch for ease of movement
• Flatseam construction and low-profile waistband and crotch gusset keep you comfortable as you move
• UPF 50+ sun protection
• Fly opening
• Ankle-length inseam
• Semifitted