While the term proof stuck, in America, the standard it refers to has nothing to do with gunpowder. Around 1848, 50% alcohol by volume was chosen as a baseline and 100 was used as its corresponding proof. Thus, the proof is double the ABV. In other countries, other proof systems are used. For example, in 1816 the U.K. started to use gravity as their standard.
Cost for rental will vary. Generic albuterol nebulizer solutions cost about $.40 for 10 doses and brand name versions can cost up to $12.10 for 10 doses, according to an analysis of national average sales prices by the Office of the Inspector General in the U.S. Department of Health and Human Services.
To use a nebulizer, you attach the nebulizer hose to an air compressor, a small machine that takes air from the environment and turns it into a high-pressure stream. The drug is placed into a small cup. Air from the compressor converts the drug into an aerosol mist that you inhale through a mouthpiece.