Poplin traditionally consisted of a silk warp with a weft of worsted yarn. The essential feature of worsted yarn is straight, parallel fibres. This preparation is commonly used to spin a worsted yarn. Roving and wool top are often used to spin worsted yarn. Twilled fabrics such as whipcord, gabardine and serge are often made from worsted yarn. The demonstration products (including worsted yarn, tartan cloth,and rugs) are made available for sale.