Ekouaer Men's Long Thermal Underwear Fleece Lined Winter Base Layering Set 95% Cotton /5% Elastane 2 Pieces Thermal Set (Top & Bottom) are made with 95% Cotton+ 5% Elastane Base-layer-underwear closure, Tagless Long sleeve top, Elastic waist with convenient fly front Ultra Soft, Warm and Comfortable; Breathable and moisture wicking, Midweight! Our size are standard US size, please choose your general thermal underwear size Machine washable. Cold weather, low-impact activities. Great to be wear alone at home or add an extra layer of warmth under your clothes