Smartwool Men's Classic Thermal Merino Base Layer 1/4 Zip

Midweight Merino thermal base layer with a 1/4 zip for adjustable warmth, breathability, and cold-weather versatility.

The Smartwool Men’s Classic Thermal Merino Base Layer Crew is a proven cold-weather essential built for dependable warmth and next-to-skin comfort. Made with 100% Merino wool, this midweight thermal layer naturally regulates temperature, wicks moisture, and resists odor, making it ideal for extended wear in cold environments.

Designed with a classic crew neck and regular fit, this base layer works across a wide range of activities including outdoor work, training, travel, and cold-weather recreation. The Merino fabric provides insulation without overheating and remains comfortable during both high-output movement and lower-activity periods.

Flatlock seam construction helps reduce chafing and improves comfort when worn under packs, armor, or outer layers. Whether used as part of a layered system or worn on its own in cool conditions, the Classic Thermal Merino Crew delivers simple, reliable performance with the natural benefits of Merino wool.

Why You Should Buy Smartwool Men's Classic Thermal Merino Base Layer 1/4 Zip

• 100% Merino Wool: Naturally warm, breathable, and odor resistant.

• Midweight Thermal Insulation: Balanced warmth for cold-weather use.

• All-Day Comfort: Soft, next-to-skin feel for extended wear.

• Layering Friendly Design: Crew neck fits cleanly under outer layers.

• Proven Cold-Weather Essential: Trusted Smartwool classic for winter conditions.