All product made of stainless steel pipes & flanges .
Lost wax made 4-1 connector with smooth inner surface for no easy cracking & no turbolence occur .
-Manifold:O/D - 42.7mm, thickness-1.8 mm
-Joint pipe(over pipe):O/D - 60.3 mm, thickness-1.8 mm
-Manifold:Engine side 12mm
4 in 1 collector 10mm
-Joint pipe(over pipe):all flange 10mm