Rigid Duct Equal T Piece Diameters 4, 5 and 6 Domus Duct T Pieces allow you to branch off from a main trunk and incorporate two additional duct runs horizontally either side, enabling flexible installation. Manufactured to exacting tolerances, which virtually eliminates air leakage and minimises pressure drop 4 Rigid Duct Equal T Piece Domus EasiPipe 100 is suitable Bathroom, Toilet and Utility room applications Free Area 7,850mm2 5 Rigid Duct Equal T Piece Domus EasiPipe 125 is suitable for Bathroom, toilet, Utility room, Kitchen and Whole House Applications. Free Area 12,266mm2 6 Rigid Duct Equal T Piece Domus EasiPipe 150 is suitable for Kitchen, Commercial and Whole House Applications Free area - 17,263mm2