Never ever dreamed of finding a Flavio Poli Sommerso piece, but here it is -- and a gorgeous one it is, too:
a vase like a monolith, 25 cm tall and weighing 4.8 kg.
Really hard to photograph due to the sobre colours (greenish grey -- pinkish red -- reddish brown).
Bought from German ebay (and the toughest buy I ever made there -- I even had to deal with the seller's lawyer to get it
Similar shaped (and sized) vase >> here
(classic Poli "Corroso" colourway; the revised description is further down -- "auction notices").
That would make mine probably Model 12403 as well?
And the colourway is the same as in these vases on Antique Helper (one of them is labeled), seem to be from the same "range": >> Link 1
, >> Link 2
Those are not as massive as mine, so the colours are a little bit clearer...
Mine has a retailer's label from a shop in Lido di Jesolo, favourite spot for German tourists from the 1950s onwards.