In addition to the usual central "spindle hole", there is traditionally at least one "drive hole" in the label area, meant to be engaged by a special pin that prevents the disc from slipping on the turntable during the recording process if the lathe does not have a vacuum turntable. Drive holes are often hidden by labels applied after the recording was cut, but they can usually be detected by careful inspection of the label or by holding the disc up to a light bright enough to penetrate the labels. Drive holes are no longer standard on lacquer masters, only on "dubs", because the additional holes can interfere with the electroforming process and professional mastering lathes use vacuum turntables that hold the workpiece (lacquer disc) in place with suction. One pump usually provides suction for both the turntable and the chip tube that pulls away the fine string of nitrocellulose lacquer removed by the groove-cutting stylus.