This is a cable for the DfRobot MiCS-4514 (SEN0377) sensor to connect to the AIR-1.
If you buy a AIR-1 with gas sensor, or you buy a MiCS-4514 sensor from us this cable is included.
You only need this cable if you are buying your own MiCS-4514 sensor. We are having trouble sourcing these sensors at a competitive price. You can use this link to find one though: https://octopart.com/search?q=SEN0377