ABB 999821 is a flexible PTFE bellows element designed for use with ABB gas sampling probes, specifically Probe H systems in Continuous Gas Analyzers (CGA). It serves as a protective and expansion component, compensating for mechanical movement, thermal expansion, and vibration in gas sampling applications.

Manufactured from high-quality PTFE (Polytetrafluoroethylene), this bellows element provides outstanding resistance to chemical corrosion and high temperatures, ensuring safe and long-term performance in harsh industrial environments. The design ensures a tight seal while maintaining flexibility under pressure.

With a gross volume of 0.522 dm³ and weight of 0.35 kg, ABB 999821 is a recommended spare part for ABB gas probe systems. It is widely used in power plants, chemical industries, and emissions monitoring applications where probe retraction and thermal compensation are critical.