a dose indicator device for a pressurised metered dose inhaler comprises an inner wheel , annular outer wheel , actuator and housing ; the inner wheel comprising primary indexing teeth and a flexible drive arm ; the outer wheel comprising secondary indexing teeth on an outer face of the outer wheel ; the inner wheel and outer wheel located at least partially within the housing such that the inner wheel and outer wheel are rotatable about a common longitudinal axis of rotation ; the actuator movable in a plane perpendicular to the axis of rotation to engage the primary indexing teeth to rotate the inner wheel ; the housing being fixed relative to the axis of rotation and comprising a deflector ; the deflector configured such that , on rotation of the inner wheel , the drive arm is intermittently deflected and brought into contact with the secondary indexing teeth to rotate the outer wheel about the axis of rotation .