The function of a screwdriver is to turn screws with slotted heads. Screws that have a single slot require the use of a flat-head or slot-head screwdriver. This is the oldest and most common type of screwdriver. Screws that have tops with a cross need a Phillips head screwdriver, which comes with a four-star point on the tip.
Screwdrivers are distinguished because of their various ends and the screws they drive. A square recess screwdriver is similar to a flat-head but is thicker, more square and does not mar the head of the screw. A Torx screwdriver is used often with electronics and appliances. A Tri-Wing is not quite as common but is used in some electronic items. A Spanner, also called snack eyes or notched, is used for everything from bathroom stall doors to electronics. An Allen hex wrench or screwdriver fits screws or bolts that have a six-sided shape on the head. Many screwdrivers come as an individual piece, but they are also available as bits for an electric screwdriver or drill. One-piece screwdrivers are made of a plastic, wood or metal handle, a shank made of tough steel and a blade that is near the tip with its various possible ends.