Sweat fabrics have become very popular for making streetwear and loungewear, because they are soft, have good isolation properties and a comfortable stretch. Sweat is a knitted fabric made with two or three yarnsystems and different yarncounts. The base is a fine, tightly twisted yarn, you will see this mainly on the front side. The back has a more fluffy, soft twisted thicker yarn that can be brushed. In some fabrics there is also a very thin third yarn to add some extra 'body' and stability to the construction.