Mac mini fan replacement: amperage rating
A Fan with 0.5Amp will do, since it will not overload the circuit, and only draw 0.5A while 0.66A is available.

It might not have enough power to provide sufficient air flow, thus it might run more, but that is only important if you run constantly at elevated Temperatures.

Check your mac mini model number to make sure it fits, since the one you are showing is for Mac Mini A1347 2010 2011 922-9953 610-0164 610-0069.