Portable gas detectors detect and display gases present in an environment. These are small and self-contained and are able to produce spot readings in the field using, for example, a hand-aspirated pump and lightweight sampling arm. The reading scales are clear and unambiguous for ease of operator use. These have different sensitivities to different materials. These are normally used for a number of different gases, whereas a fixed detector may be calibrated for one specific gas and fastened in place.

Portable Gas Gravitometer is a tool for spot-checking process gas mixtures through an analysis of the specific gravity. This gravitometer is a direct weighing type instrument and constructed to measure the difference in the weight of a column of gas and an equal column of dry air. Gravitometer provides a 4-20 mA output for process control and has alarms for out-of-range measurements.