Side by side comparison of two widely available CSST systems. (Corrugated stainless steel tubing) Gastite uses a metal to metal seal while ProFlex uses a dual sealing gasket system.

Proflex manufacturers site:
http://www.proflexcsst.com/

Gastite manufacturers site:
http://www.gastite.com/

Other Info:
http://www.csstsafety.com/