Abstract: A manually operable setting stem 1 has three stable axial positions defined by a pull out piece 4 cooperating with notches in the head 8a of a spring 8. The illustrated position is a pushed in, neutral position. In an intermediate pulled out position, a return bar 9 moves a sliding pinion 12 into engagement with a gear 17 in mesh with a gear 18 which is in turn in mesh with a gear 19 whose axis can swing about the axis of the gear 18. In the intermediate position, rotation of the stem in one sense adjusts a data ring 14 via a star-wheel 20 on the gear 19; rotation in the other sense adjusts the pre-set alarm time via a gear 21. In the fully pulled out position the return bar slides the pinion 12 further inwardly and with it the gear 17 which meshes with a gear 24 for setting the time indicating mechanism. The stem can be pushed in beyond the stable pushed in position to engage the tip 1a of the stem with an electrical contact. Such operation alternately turns the alarm mechanism on and off.