A corkscrew is a tool for drawing stopping corks from wine bottles. Generally, it consists of a pointed metallic helix (often called the "worm") attached to a handle. The user grips the handle and screws the metal point through the cork, entwining the cork and corkscrew so that moving one moves the other. Corkscrews are necessary because corks themselves, being small and smooth, are difficult to grip and remove, particularly when inserted fully into an inflexible glass bottle. The handle of the corkscrew, often a horizontal bar of wood attached to the screw, allows for a commanding grip to ease removal of the stopper. Corkscrew handles may incorporate levers that further increase the amount of force that can be applied outwards upon the cork.