The HeroBiker Men's Winter Thermal Top and Bottom Plus Size Set is made from super soft polyester and micro fleece with four-way stretch fabric, designed to provide extreme warmth and comfort in cold weather. This breathable and moisture-wicking set helps keep you dry and light, while its four-way stretch material ensures full mobility and a comfortable, second-skin fit. Easy to care for and machine washable, this durable thermal underwear set is perfect as a base layer for various outdoor activities like skiing, biking, hiking, or for everyday work and leisure, offering lasting warmth and shape retention.