A device for dispensing a material under pressure, including at least one elastic portion defining at least one wall of a chamber defining a volume within which the material is to be contained; and at least one non-elastic portion coupled to the at least one elastic portion and affecting a geometry of one or both of the elastic portion and of the chamber; wherein, at least when the material is contained within the chamber, the at least one elastic portion is stretched so as to urge a reduction in volume of the chamber by at least 70%. The non-elastic portion is optionally rigid.