Comp 4 Women's Zip Mock provides the ultimate in warmth in the coldest temperature. Simplybest and warmest performance base layer. Ideal for layering piece, or wear it alone. Heavy weight 4-Way stretch fabric. Tech Face-Brushed Interior Fleece/ 90% Acclimate Dry, 10% Spandex. Wicks, Breathes, Quick Drying. Material: Fleece, Spandex.