Embodiments of battery holders with dual-contact assemblies are disclosed. In addition, such an interior member is formed in accordance with a reaction injection molding method. Finally, the processor unit apportions the total usage measurement to the single unit based on the correlated data. In one predetermined total-air function in the control unit, the sum of total-air rate composed of the rate of compressed conveying air and of the rate of supplemental compressed air can be kept constant even if the rate of compressed conveying air changes. The compounds are useful for the treatment of diseases such as diabetes.