Are there any single-plug (not "powerstrip"-style) adapters that can work for Italy, France, the UK, and Switzerland? It seems very cumbersome to have to pack 4 types of adapters.
'European' outlet, used in continental EU-countries
Outlet used in island countries of EU (Britain, Malta, Cyprus, Ireland)
Swiss outlet
(Image sources - http://tripolo.pl/turystyka/porady/standardy-napiec-i-wtyczek-elektrycznych-na-swiecie/)
Update: Both the answers provide what I was looking for, but given the cost and the lack of product reviews on those type of items, I decided against it. I was looking for an adapter from US to Country XYZ that would work for all countries in Europe.