The T-piece can be installed in two different parts of a ventilation system. The T-piece can be fitted at the end of the ductwork, with the small port used as a cleanout. The T-piece can also be installed at corners of the ductwork, with the small port sealed with the end cap to work as an expansion (plenum) box. The blind end cap can always be removed to access the main duct.
The insulated T-pieces are clad in sound-proofing rubber.
