Copper alloy (brass) or stainless steel is the standard wetted parts (materials in contact with the pressure media) available on most pressure gauges. Since the sensing element of a pressure gauge may be exposed directly to the measured medium, consider the characteristics of this media. It may be corrosive, solidify at various temperatures, or contain solids that may leave deposits inside the sensing element. For pressure fluids that will not solidify under normal conditions or leave deposits, a standard bourdon tube gauge may be acceptable. Otherwise, a seal gauge or gauge with a chemical seal/gauge protector should be used.