The RefrigiWear Lightweight Mid-Layer Thermal Top adds 4-8degree(s)F of warmth, making it the ideal base layer for cold or industrial environments. Made from a 92% polyester and 8% spandex 4-way stretch blend (160g), it moves with you while locking in heat. A raised crew neck, brushed lining, and flat seams enhance comfort and reduce friction. Available in sizes S-5XL, this durable undershirt keeps you warm, comfortable, and ready to tackle any job in frigid conditions.