The invention relates to a device for compacting a sliver on a spinning machine, the sliver being delivered by a pair of delivery rollers of a drafting system unit to a suctioned guide surface of a suction zone of a subsequent driven, revolving compaction element that is acted on by suction air. The end face of the second flange, which is directed toward the first flange, includes an annular groove and a sealing element is disposed within the annular groove. In some embodiments as the likelihood of winning the mystery bonus increases, the award for winning the mystery bonus decreases.