What Our Gearhead(R) Experts Are Saying: "I use this as my go-to midweight base layer in winter. The 250-weight merino feels warm without overheating, and the updated slim fit layers cleanly under a fleece or shell. The flatlock and offset seams make a noticeable difference when I'm carrying a pack or moving all day."When temperatures dip and the day's objective calls for steady effort, the Merino 250 Baselayer Crew Boxed Top from Smartwool forms the foundation of our layering system. Built for skiing, hiking, climbing, and cold-weather rides, it delivers dependable warmth with natural performance benefits. Made from 100% merino wool in a soft interlock knit, this base layer manages moisture, regulates temperature, and resists odor through long days outside. The slim fit follows the body's contours for efficient layering, while flatlock construction and offset shoulder and side seams help minimize chafing under pack straps. With forward-wrapped side seams and improved fit details, this crew is designed to move comfortably from first chair to final descent.