These flanges had several applications in the Trafic, most notably on the front downpipe where it met the manifold, but also on some of the silencer sections. See below for fitment:
Downpipe: 2.0 and 2.2 petrol, 2.1 diesel.
First silencer: 2.1 and 2.5 diesel (later models with the 3 silencer systems)
These flanges were usually integral to the section, in other words the end pieces were welded on afterwards so these are generally only useful when carrying out repairs.
Also used on many other Renaults of the era, as well as by several other French manufacturers.
Brand new, excellent quality.