WINDOWS 10 PROFESSIONAL.
Windows 10 Professional KEY (32/64 Bit) works only for Windows, not for Mac!
Windows 10 Home, Windows 7 Home Basic/Premium and Windows 8.1 CoreCountrySpecific/CoreSingleLanguage/Chinese (incl. WMC) CANNOT be directly upgraded to Windows 10 Professional by changing product key in Windows system. If You have these editions on you computer, you need to make a clean installation after purchasing Windows 10 Professional.