The invention relates to the type of housing (107 310 410 510) used to carry an inhaler canister (12) for delivery of an active agent. The inhaler housing has a body (16 316 416 516) for receiving the inhaler canister and a mouthpiece (14 314 414 514) which is to be placed in the mouth of a user and through which a dose from the inhaler canister is to be delivered. In one embodiment the body and the mouthpiece are rotatably coupled to one another so that by turning the mouthpiece relative to the body the inhaler housing is reversibly converted between a carry configuration in which the mouthpiece and body are mutually aligned and a use configuration in which the mouthpiece projects laterally from the body. The inhaler housing has a member (26) which is variably elastically deformed as the mouthpiece is turned relative to the body investing the member with elastic potential energy which varies with the mouthpieces rotational position with respect to the body and which has at least two minima corresponding to the carry configuration and the use configuration respectively so that rotation of the mouthpiece relative to the body tends to stop when either of these configurations is reached.
