The Jerome 631-XE utilises a patented gold film sensor. The sensor's selectivity to hydrogen sulphide eliminates interferences from sulphur dioxide, carbon dioxide, carbon monoxide, and water vapours. When the sample button is pressed, an internal pump draws air into the instrument. Any hydrogen sulphide in the sample is adsorbed by the sensor which registers a proportional change in electrical resistance. The hydrogen sulphide concentration is displayed on the LCD, where it remains until the next sample is taken.

Additional accessories are available to customise the Jerome 631-XE to meet individual application needs. For unattended sampling, the instrument can be programmed by a computer using the Jerome Communications (JCS) software. A data logger plugs into the back of the instrument for data acquisition during portable surveys or unattended sampling without a computer. Recorded data can be downloaded later to the computer using the JCS software for analysis printout, permanent record keeping. An internal option board allows autozeroing, DC power operation, timed regeneration, and timed sampling during prolonged unattended sampling periods. The option board also allows external fresh air solenoid support and 4-20 mA or 0-2 V analogue output. A moulded hard carrying case or soft field case give added versatility and organised storage for the instrument and its accessories.