The ICCT3505 from Centrotherm is a 3”/5” Innoflue Concentric to 3” Twin Pipe Adapter. This adapter allows to transition from 3"/5" Innoflue concentric pipe (male end) to two 3" single wall (SW) pipes. Exhaust pipe is 3" Innoflue SW (single wall) pipe, female (hub) connection - installed in the same manner as the rest of the single wall piping (requires a 3" IANS03 connector ring - sold separately). Air intake is the same size as 3" Innoflue SW male pipe end - can be used in combination with 3" Innoflue pipe or transitioned to other approved pipe (i.e. PVC/CPVC) using a flexible rubber coupling (using glue/cement is not recommended).