The Mountain Warehouse Men's Keep the Heat Thermal Top is a versatile cold-weather essential, crafted from a blend of 37% Acrylic, 32% Polyester, 25% Viscose, and 6% Elastane for a comfortable fit. This plain-styled top features a crew neckline and long sleeves, making it ideal for layering under jackets during the winter months. Equipped with Isotherm fabric technology, this thermal top boasts lightweight construction, moisture-wicking properties, and quick drying capabilities to keep you warm and dry in cold conditions. Sizes range from XXS (33 inches) to 4XL (56 inches), ensuring a perfect fit for all.