Named Best Overall Base Layers for Women by GearJunkie (2025-2026). Meet the new and improved Women's Classic Thermal Merino Base Layer Crew. We've updated this 100% Merino wool fan favorite with new color options and an enhanced fit to improve functionality while elevating aesthetics. The addition of shoulder panels and its flatlock seam construction help prevent chafing and increase your comfort level. Add one of our best base layers for cold weather to your winter wardrobe and experience the difference the next time you go skiing, hiking, climbing, or biking.