In Cuba there are two currencies in circulation. The CUP is the "currency of Cubans," is the Cuban peso and is used since the country's independence. The CUC (convertible peso) is the "currency of yumas* " and was created in the 90s. * foreign 1 CUP is worth 1/24 of the U.S. dollar (+ - 4 cents). 1 CUC is worth on average $ 1. See the currency images at: http://www.numisbrazilis.blogspot.com.br/2013/04/cup-e-cuc.html
Is there a reason all of the CUC Notes are marked "specimen"? That usually means it is not to be used for circulation.
the CUC is the currency of cubans too. There is no numismatic value for those convertible pesos. Cubans are paid in cuban pesos but if they want to buy something in the gov stores they have to pay with CUC.
Many communist countries had separate currencies for visitors or notes that were good only in certain places. China, North Korea, Cuba, East Germany, Vietnam and Poland all had them at one time.
They use US$ and Euros whenever possible. Sometimes in the past it was legal, other times like now it is not.
Many countries have one "currency" used in different ways by locals and tourists. When visiting Egypt in the late 80's, I recall getting 10 piastre notes on the street, but at the tourist sites it was pretty much pounds only. Locals were buying bread for 3-5 paistres. Tourists - don't even think about it. Even though 100 piastres = 1 pound, they seemed to exist in separate universes.
