Grsync installation under Windows
Project homepage of Grsync for Windows: http://grsync-win.sourceforge.net/
Installation program:
http://sourceforge.net/projects/grsync-win/files/grsync-win/Windows%20Installer/grsync-setup-0.6.3.exe/download
Selection of installation folder: 
Finishing installation: 
Graphic interface of the program: 
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Grsync package contains own Cygwin environment installation, which can coexists in Windows with the regular Cygwin installation, but in the Grsync package is included own (mostly older) version of line rsync client, which is used by Grsync to transfer the files, this fact may be a bit confusing.
For use cases please go back to: Rsync