Industrial Scientific 17134487 CO Sensor for MX4 Multi Gas MonitorsReplacement CO (Carbon Monoxide) Sensor for the Ventis MX4 Multi-Gas Monitors.Features:Detects: Carbon Monoxide (CO)Range: 0 to 1000 ppm1 ppm ResolutionTemperature Rating: -4 to 122 FFor Use With: Ventis MX4 Multi-Gas Monitors