arms 5 a the guide sleeve 5 can therefore only be rotated in a direction of rotation specifically defined by the snapper arm profile whereas a rotation in the opposite direction is blocked or prevented the guide sleeve 5 has an internal thread 5 b on the internal face in which the external thread 4 b of the rod 4 is guided the snapper arms 5 c provided on the guide sleeve 5 constitute a releasable anti rotation lock element and engage in the teeth of the toothed thread 4 b of the rod 4 so that the snapper arm 5 c is coupled with the rod 4 and the rod 4 and guide sleeve 5 form a unit if too high a dose is set when rotating the dose setting sleeve 1 the dose setting sleeve 1 can be rotated in reverse or backward to adjust i e reduce or correct the dose during the backward rotating movement the dose setting sleeve 1 display barrel 2 spring tensing sleeve 6 toothed threaded rod 4 and guide sleeve 5 are coupled or locked together to form a unit locked so as to rotate in unison in particular due to the anti rotation lock 1 a 2 a and the snapper arm 2 c of the display barrel 2 the dose setting sleeve 1 is coupled so that it rotates in unison with the rod 4 which is also rotated backward when the dose setting sleeve 1 is rotated backward during this backward rotating movement however the rod 4 is not moved in the axial direction the guide sleeve 5 is coupled by the snapper arms 5 c with.