Sierra Flame 3" x 6" Flex To Rigid Duravent Adapter

When converting the Langley flex venting to rigid duraVent, the SFDURA-FLEX adapter is | SFLANGTTRK-ADP. From the Langley fireplace a section of 3" and 6" flex venting connects to SFLANGTTRK-ADP. Next the SFDURA-FLEX connects to the SFLANGTTRK-ADP. Now 4" x 6 5/8" rigid may be used.