A device for retaining a self-closing valve in a closure is provided. The device comprises a body for receiving a self-closing valve and having a crimping flange capable of being bent from an uncrimped position to a crimped position so as to retain the valve in the device. The body is receivable into a closure with the valve retained. The crimping flange has a length, for instance, generally within a range of 0.5 mm and 4.0 mm.