Ecko Function Thermal Set Black 2PC Waffle Knit Base Layer Underwear XL The Ecko Function Thermal Set in Black is a 2-piece waffle knit base layer underwear set designed for men. Made from polyester material, these long johns are machine washable and feature a solid gray color. With a focus on functionality, this set is perfect for all seasons, providing warmth and breathability. The Ecko Unltd. brand ensures quality and reliability, making this set a comfortable and stylish choice for men's clothing.