Light-emitting devices and associated methods are provided. A first die is back bonded to the substrate and encapsulated in a first encapsulant, and a second die is back bonded to the first encapsulant. A collapsible storage container having an attachment mechanism is provided which is capable of being moved from a collapsed position to an operative position. It is therefore possible to reliably discharge a desired amount of fuel gas by deciding a closing time at which the discharge valve is closed based on the integral value or the parameter value.