A length-adjustable unit includes a tubular outer component, an inner component displaceably guided in the outer component, issues from the outer component and arranged outside of the outer component has a connecting element, and an additional connecting element arranged at the assembly end, opposing the exit end, of the outer component. The additional connecting element, or an intermediate element rigidly connected to the assembly end of the outer component, has at least one annular shoulder extending in the circumferential direction of the outer component over the full 360°, while at least one engaging element is associated with the intermediate element, which is rigidly connected to the assembly end of the outer component, or the additional connecting element, and this engaging element is engaged with the annular shoulder to be slidingly displaceable in the circumferential direction but positively engaged in a longitudinal direction.