Slotted screws are driven with a straight blade screwdriver that fits the slotted drive; this is the oldest and simplest drive form. The disadvantage of this drive is that it can twist out under torque especially if the screw slot or driver tip becomes worn. Commonly found on tapered thread woodscrews and parallel thread machine screws in domestic applications or where field retightening or removal may be required. It has many applications, but is not suitable for power driver use.