A device for dispensing a material under pressure, comprising: at least one elastic portion being made of elastomeric material and defining at least one wall of a chamber defining a volume within which said material is to be contained; and at least one non-elastic portion coupled to said at least one elastic portion and affecting a geometry of one or both of said elastic portion and of said chamber; wherein, at least when the material is contained within said chamber, said at least one elastic portion is stretched so as to urge a reduction in volume of said chamber by at least 70%; characterized in that said at least one elastic portion and said at least one non-elastic portion form a structure selected from the group consisting of: (i) a structure in which said at least one non-elastic portion comprises two rigid portions (1704, 1704a), and in which said at least one elastic portion is a band around said volume that interconnects perimeters of said two rigid portions (1704, 1704a), such that contraction of said band reduces a separation between said two rigid portions (1704, 1704a); and (ii) a structure in which said at least one elastic portion comprises two elastic portions (2102, 2102a) facing each other, and in which said at least one non-elastic portion comprises a rigid portion that maintains a shape of said chamber along at least one dimension thereof, and that is provided in two parts which clamp said two elastic portions (2102, 2102a) therebetween. at least one elastic portion being made of elastomeric material and defining at least one wall of a chamber defining a volume within which said material is to be contained; and at least one non-elastic portion coupled to said at least one elastic portion and affecting a geometry of one or both of said elastic portion and of said chamber; wherein, at least when the material is contained within said chamber, said at least one elastic portion is stretched so as to urge a reduction in volume of said chamber by at least 70%; characterized in that said at least one elastic portion and said at least one non-elastic portion form a structure selected from the group consisting of: (i) a structure in which said at least one non-elastic portion comprises two rigid portions (1704, 1704a), and in which said at least one elastic portion is a band around said volume that interconnects perimeters of said two rigid portions (1704, 1704a), such that contraction of said band reduces a separation between said two rigid portions (1704, 1704a); and (ii) a structure in which said at least one elastic portion comprises two elastic portions (2102, 2102a) facing each other, and in which said at least one non-elastic portion comprises a rigid portion that maintains a shape of said chamber along at least one dimension thereof, and that is provided in two parts which clamp said two elastic portions (2102, 2102a) therebetween. (i) a structure in which said at least one non-elastic portion comprises two rigid portions (1704, 1704a), and in which said at least one elastic portion is a band around said volume that interconnects perimeters of said two rigid portions (1704, 1704a), such that contraction of said band reduces a separation between said two rigid portions (1704, 1704a); and (ii) a structure in which said at least one elastic portion comprises two elastic portions (2102, 2102a) facing each other, and in which said at least one non-elastic portion comprises a rigid portion that maintains a shape of said chamber along at least one dimension thereof, and that is provided in two parts which clamp said two elastic portions (2102, 2102a) therebetween.