Holder for inhaler article with inhalation volume estimator

A holder for an inhaler article, the holder comprising an inhalation volume estimator and an air flow passage, the inhalation volume estimator comprising:

• a turbine;
• an indicator coupled to the turbine for indicating inhalation volume information relating to a volume of an air flow through the air flow passage;
• and
• a modifying mechanism coupled to the indicator for resetting or otherwise modifying the inhalation volume information,
• wherein the turbine is configured to rotate in response to air flow through the air flow passage and alter the inhalation volume information indicated by the indicator,
• and wherein the modifying mechanism is operable by one or both of engaging the inhaler article with the holder and disengaging the inhaler article from the holder.