Many modern electrical appliances, if they contain screws, use screws with heads other than the typical slotted or Phillips styles. Torx is one such pattern that has become widespread. It is a spline tip with a corresponding recess in the screw head. The main cause of this trend is manufacturing efficiency: Torx screwdriver tips do not slip out of the fastener as easily as would a Phillips or slotted driver. (Slotted screws are rarely used in mass-produced devices, since the driver is not inherently centered on the fastener.)