Wastewater Monitor - The direct connect series gas sensors are highly reliable and very cost-effective for the detection of common gas hazards. The direct connect series are available for LEL, Oxygen, H2S, and CO. All sensors are explosion-proof with flame arrestors and are approved for use in hazardous locations. The tri-sensor head can be used either indoors or outdoors and the flame arrestors for the explosion-proof versions utilize a patented coating which makes them water repellent. Also, splash guards are available for use in very wet environments.