The Reznor 205546 Compression Coupling Assembly is a durable replacement component designed to create a secure, leak-resistant connection between compatible tubing or piping in HVAC systems. It works by compressing the fitting around the tubing, ensuring a tight seal that helps maintain proper airflow or gas flow while minimizing the risk of leaks. Commonly used in Reznor unit heaters... https://www.partshnc.com/compression-coupling-assembly