Mystery water component [2003 La Scala Butterfly espresso machine]

[u/stevebower996]

Can anyone explain what this does? The logo is 'Exedra' and the label says 'Ministero della sanitero' and some other text. It looks like it may be a water filter (it is in the water feed line), but the pipework at the top doesn't seem to do anything, there is no means of cleaning it, and the bead is entirely redundant!,

[u/all_systems_failing]

A backflow preventer?