See this pdf from Poste Italiane for rates that became effective 10 March 2019.
Page 38 lists rates by zone (zona) for shipping a package (pacco).
The USA (Stati Uniti) is in Zone 4, as shown at the top of page 64.
Consequently, the rate listed on page 38 for a standard size box (described below the table and explained at the bottom of this response in the note) going to a Zone 4 country is € 60.
Insurance rates are noted in Table 1 on page 38, with the maximum insurable amount varying by country. For a shipment to the U.S., the maximum insurable amount would be € 1951.44 as shown in Table 2, page 41.
Note: A standard size box is one measuring no longer than 105 cm (41 inches) in the longest dimension, with a maximum dimension (that length plus the distance of a complete rotation around the box, not including the longest dimension) of 200 cm (78.7 inches, or about 6 feet 6 inches).
In other words, if you had a rectangular box that was 60 cm on its longest side, had one other side that measured 20 cm, and the other side measured 40 cm, that would be a standard size box because the longest dimension would be less than 105 cm and the maximum dimension would be 60+20+40+20+40 = 180 cm, which comes a little under the maximum allowable of 200 cm.