An adapter 1 for fitting to a drug delivery inhaler device, the adapter comprising: a holding chamber 2 with an inlet 3 for connection to a mouthpiece of the inhaler device； a spacer portion 4 having an outlet 5 for communication with the mouth of a user； a valve 7 positioned between the chamber and the spacer portion； an air flow path through the adapter along which air is drawn to the outlet by the user inhaling； an air flow rate indicator 6 positioned between the valve and the outlet, where the indicator is operable to indicate when the air flow rate along the air flow path is at a predetermined minimum level and/or above a predetermined maximum level suitable for delivery of a drug to the user. The indicator may generate an audible or a visible signal. The indicator may comprise at least one pressure driven mechanical oscillator. The predetermined minimum level for the rate of air-flow may be at least 15 litres/min. The predetermined maximum level for the rate of air-flow may be about 90 litres/min. The spacer-portion may be tubular. The spacer-portion may be detachable from the chamber. Also disclosed is a kit.
