Lace was first manufactured in 1808 on the Heathcoat machine. Derivatives of this machine include the Leavers and Nottingham machines introduced in the middle of the 19th century. These machines, which were fitted with brass bobbins, operated by twisting rather than interlacing the yarns. The Leavers machine produces dressing lace for both outerwear and innerwear while the Nottingham machine produces table and window coverings. Raschel and jacquard machines are also currently used; some feature electronic or computer control. Patterning capabilities are determined by the number of guide bars.