A delivery device includes a toroidal shaped housing defining an interior chamber and a central open space. The housing includes an input port communicating with the interior chamber and a delivery port positioned on an inner periphery of the housing. The delivery port is in fluid communication between the interior chamber and the central open space. The delivery port is spaced from the input port, which is adapted to receive an aerosolized medicament. In another aspect, a kit includes an outer ring-like housing component and a plurality of differently configured inner ring-like housing components mateable with the outer ring-like housing to form a holding chamber. A method of delivering an inhalable substance is also provided. A mask, including mounting and sealing portions is also provided, together with a method of manufacturing such a mask. Delivery devices include various alternative adapters to be used with a mask and a substance dispenser.