Smartwool Classic Merino Base Layer LS Boxed - Black, Size L

Engineered with 100% ZQ-certified Merino wool at a substantial 250 g/m², this heavyweight base layer top delivers exceptional warmth and next-to-skin comfort for cold-weather pursuits. The fabric naturally regulates temperature, wicks moisture, and resists odour, while flatlock seams and offset shoulder seams eliminate chafing under pack straps. Ideal for skiing, snowboarding, and winter hiking, it offers a slim fit with long sleeves and a crew neck. UPF 20+ protection and easy machine-wash care complete this versatile piece.

Overview

The Smartwool Classic Merino Base Layer LS Boxed is a men's long-sleeve top designed for high-output activities in freezing conditions. Its heavyweight 250 g/m² Merino wool fabric provides excellent insulation without bulk, while the slim fit allows for easy layering under midlayers and shells. The crew neck and long sleeves offer full coverage, and the flatlock seam construction ensures a smooth, irritation-free feel. Whether you're carving down slopes or trekking through snow, this base layer keeps you dry, warm, and comfortable all day long.

What stands out

• 100% ZQ-certified Merino wool for ethical sourcing and superior performance
• Heavyweight 250 g/m² fabric for maximum warmth in extreme cold
• Naturally moisture-wicking, odour-resistant, and breathable
• Flatlock seams and offset shoulder seams prevent chafing under pack straps
• UPF 20+ sun protection for high-altitude exposure
• Machine washable for easy care and long-lasting durability

Technical details

• Material: 100% ZQ-certified Merino wool
• Fabric weight: 250 g/m²
• Fit: Slim
• Sleeve length: Long sleeve
• Neckline: Crew neck
• Thermal rating: Heavyweight
• Seam construction: Flatlock seams
• Shoulder design: Offset shoulder seams
• UPF protection: UPF 20+
• Care: Machine wash cold, gentle cycle; tumble dry low; do not bleach, iron, or dry clean
• Ideal use: Skiing, snowboarding, winter hiking, cold weather activities

Our verdict

A premium heavyweight base layer that excels in the coldest conditions. The ZQ-certified Merino wool offers unmatched comfort and performance, while thoughtful details like offset seams and flatlock construction make it a reliable choice for serious winter athletes. If you need warmth without compromise, this is it.