596699 A dose setting mechanism (200) for a drug delivery device comprises an outer housing (204), an inner housing (208), a driver (209), a dial sleeve (206) disposed between the outer housing and the inner housing, and a dose dial grip (202) rotatably coupled to the dial sleeve. The inner side of the dial sleeve is rotatably engaged with an external groove (see 232, figure 10) of the inner housing, which is advantageous in allowing greater outer surface area for a scale arrangement (see 242, figures 12 & 13) and also makes it more difficult for dirt from outside the mechanism to become logged in the groove. The dial grip is non-rotatably coupled to a dose button (216). To set a dose, the dose dial grip is rotated with respect to both the outer housing and the inner housing, such that the dial sleeve is translated away from both the outer housing and the inner housing. The inner housing is operatively coupled to the driver and guides the driver to dispense a dose set by the dose setting mechanism.
