Abstract:
A holder and/or a holder and cover for containing a dispenser of a consumable product, such as a cartridge containing pressurized gas for therapeutic use, and a method for selecting the optimum parameters for such holder are provided to allow sensitive determination of the amount product remaining in the dispenser. The holder has a curvilinear or partly curvilinear circumference, and holds the dispenser so that the center of mass of the dispenser and the product it contains is at a predetermined optimum location relative to the center of mass of the holder. Thus, when the holder is placed on a horizontal surface, the holder can roll along the curvilinear circumference, and the predetermined optimum relationship of the center of mass of the dispenser and the center of mass of the holder causes the holder to come to rest at adequately spaced unique locations on the circumference of the holder depending upon the combined mass of the dispenser and the product it contains. Markings placed on the external surface of the holder can then be used to determine the amount of product remaining in the container. The holder is preferably made of plastic and can be composed of a fluorescent plastic to permit the dispenser to be easily located, grasped and removed for use, and then replaced after use, even in the dark.