The Honeywell WEB-600 / WEB-600E is a wall-mounted CO₂ transmitter designed for indoor air quality (IAQ) monitoring in commercial and industrial spaces. Its NDIR sensor ensures stable, drift-free CO₂ measurements for 15+ years, while the analog/digital outputs integrate with HVAC systems. The WEB-600E variant is ATEX-certified for use in hazardous areas (Zone 2).