A twin unit has two drafting devices for drafting fiber strands and is applicable in a spinning machine. The twin unit includes a common housing for the two drivable drafting devices, whereby the housing is detachably mounted in a machine frame. The drafting devices include a number of drivable bottom rollers and are arranged essentially mirror-symmetrical to one another. Each bottom roller has an area which drafts the fiber strand and is characterized in that the bottom roller has two bearing points. The two bearing points of each bottom roller are arranged one on either side of the area which drafts the fiber strand. In one variation, at least two opposite bottom rollers may form a bottom roller pair, in which the bearing points facing to the plane of symmetry of the twin unit are taken up in a joint bearing take-up. In addition, a top roller in the form of a twin pressure roller may be assigned to a bottom roller pair.