A container or vial (1) for a fluid, the container (1) comprising a casing defining an interior for storage of the fluid and a closure member (2). The closure member (2) comprises a body and at least one resilient projection (7) to seal in a storage condition an outlet of the casing, wherein upon an increase in the pressure of the interior of the container (1) the at least one resilient projection (7) is deflected to accommodate outflow of fluid through the outlet. The pressure in the interior of the container (1) may be increased by displacing the closure member (2) into the container (1) or by displacing some other element such as a bung (61, 82) into the container (1). The container (1) and closure member (2) may be used in a dispenser (90) and the closure element may be used in a valve (110).