The Mesa Laboratory DryCal 500 is a metrology series high accuracy gas flow calibrator. The DryCal line is completely dry using no hazardous mercury seals and requiring no bubble solution or oil. There are 3 measuring cells that cover flow ranges from 5 sccm to 50 slpm, and have accuracy ranging from 0.20 to 0.45% of reading. You can measure volumetric or standardized flow in suction or pressure mode. The unit is easy to use with a backlit LCD display. You can interface with a PC using the free downloadable software.