about the fulcrum 308 of the internal housing 307 in a proximal direction by virtue of the location of the second pivot 343 of the lever 340 within the slot 315 of the drive member 314 the piston rod 310 is prevented from moving proximally by interaction of pawl means 345 of the internal housing 307 with the second set of indentations 311 and 311 u2032 of the piston rod 310 as the drive member 314 travels in the proximal direction relative to the piston rod 310 the lugs 341 of the lever 340 are displaced transversely by interaction with the first set of indentations 309 and 309 u2032 of the piston rod 310 the proximal travel of the drive member 314 is limited by the guide slots not shown of the internal housing 307 at the end of the travel of the drive member 314 the lugs 341 of the lever 340 engage with the next sequential indentation of the first set of indentations 309 and 309 u2032 of the piston rod 310 as indicated in fig1 the action of the lugs 341 of the lever 340 positively engaging the first set of indentations 309 and 309 u2032 of the piston rod 310 under a force provided by the transverse deflection of the lever 340 creates an audible and tactile feedback to the user to indicate that the dose has been set additionally visual feedback regarding dose setting may optionally be indicated by a graphical status indicator provided on the drive member 314 which can be viewed through an optional window aperture in the main housing part 303 when the dose has been set the user may then dispense this dose by depressing the dispensing face 319 of the activation part 316 of the drive member.