LONG SLEEVE T-SHIRT TO KEEP YOU WARM: This kids' long sleeve t-shirt features Damart's innovative Thermolactyl technology. It will keep you warm in all circumstances. The cold will be a bad memory! Whatever your activity, this thermal underwear will bring you warmth and comfort. TECHNOLOGY FOR YOUR SKIN: Thermolactyl Sensitive underwear keeps you warm while preserving the hydration of the surface layers of the skin, thanks to its innovative technology. (+23% hydration after 4 hours of wear! Test performed on 11 people. Average value measured on the surface layer of skin after 4 hours of cover.) Two in one advantage for optimal comfort! A DEGREE OF HEAT 2: Damart underwear using Thermolactyl smart material is divided into 5 heat levels. This warm underwear is 2 degree: it is ideal for use when ambient temperatures range from 5° to 15°. It will generate a comfortable heat and chill out in a blink of an eye. COMPOSITION AND MAINTENANCE: This Thermolactyl t-shirt is machine washable at 40° and can be tumble dried (rotary drum drying) at moderate temperature and normal cycle. Do not bleach or steam iron. Iron at low temperature (10°C). Main Composition: 82% Acrylic, 12% Other Fibres, 6% Elastane. DAMART, INNOVATION AND PROTECTION: Created in 1953, Damart designs tomorrow's solutions to provide quality clothing with respect for human beings and the planet. Our engineers develop exclusive, revolutionary labels to give you more comfort, warmth in cold weather, cool in hot weather, freedom of movement, and more tips to simplify your life.