Sometimes, a generic just won't make the grade. That's when you reach for the RefrigiWear Thermal Lined Sweatshirt with a heavy-duty 310-gram outershell and a 180-gram thermal knit lining. These two layers of warmth provide extra insulation that can keep you warm when the weather turns nasty.Sizing Instructions: For the most accurate fit, take your measurements over the base layer of clothing you intend to wear with this RefrigiWear gear (such as thermal underwear, jeans or a sweatshirt) and refer to the size chart for this product.