<puts nerd hat on>
The black plug on the left has ~5mm pins, the Apple duckbill on the right has 4mm pins. Outside Italy and Switzerland, it doesn't matter--they both fit--but the black plug doesn't actually meet the Europlug standard.

Nearly all Italian outlets have the overlapping hot/neutral pins, because Italy has two plugs dating back to the days when electricity was sold at different rates for light vs. other uses. The narrower pair is for the 10A plug with 4mm pins and the wider pair is for the 16A plug with 5mm pins. The French/German plug has 5mm pins with the same spacing as an Italian 10A plug and won't fit in the ubiquitous "bipasso" outlet because the pins are too fat (and wouldn't ground even if it did fit). The solution is the "multipasso" outlet that takes both types of Italian plugs and a Schuko. They take up more space, though, and they're not required to be installed anywhere so they tend only to be in hotels and new construction (particularly kitchens).


Italian outlets:

"bipasso" on left, "multipasso" on right. Note how the inner set is narrower on the bipasso but both sets are the same size on the multipasso--that's what enables a Schuko plug to fit.

boberonicus, if your Schuko adapters fit in the bipasso outlet, that means it doesn't actually meet the standard... but if it's a non-grounded device, who cares. ETA: I totally have a couple of these around the house, and they do indeed have ~4mm pins.

All that said, thanks to globalization and the EU single market, if you walk into an Italian shop and buy a kitchen appliance there's a decent chance it'll have a Franco-German plug on it, which means that Schuko to Italian plug adapters are sold literally everywhere for a couple Euro.

Thanks for watching this episode of der_saeufer's electricity hour. We'll see you next week for "how to use a pencil to jam a Europlug into a UK outlet".
<nerd hat off>