General Monitors’ PA4000 photoacoustic gas monitor uses infrared sensing technology for accurate measurement of gas vapors with minimum interference from other vapors. The monitor provides monitoring for gases such as hydrocarbons, solvents, alcohols, CO2, CO, and toxics. With a range of 0–1,000 ppm depending on the specific configuration, the monitor is accurate to +/-2 ppm at 0–100 ppm and +/-10 percent of reading from 100-–1000 ppm. The unit features sensitivity of 2 ppm and resolution of 1 ppm, with specifications for other ranges dependent on application. For certain gases, it detects concentrations as low as 0.01 ppm. The monitor operates over a temperature range of 32 F to 122 F (0 C to 50 C) and has a storage temperature range of -67 F to 158 F (-55 C to 70C). It has a temperature (https://www.flowcontrolnetwork.com/measurement/temperature#en) effect of +/-0.3 percent per degree (C) of reading and operates at a humidity range of 0–95 percent relative humidity, non-condensing. The monitor can be configured to monitor from up to eight remote areas, with standard features including a vacuum fluorescent display, audio alarm and four relays. The unit can be housed in general purpose, explosion-proof or rack-mount enclosures. It also offers standard 4-20 mA and 0-10 V outputs.