Two of the four variations ...
Not only one actually, you get four! variations. Although they all use the Equinox theme engine, but they all have different color choices thus gives a complete different "taste" by each. The theme suit come with a metacity, GTK+ and a Chrome browser theme as well.
You can easily install all four Equinox themes in Ubuntu by using a PPA channel. To do that, we have to first install the Equinox theme engine first. Open your Terminal and issue the below command first.
sudo add-apt-repository ppa:tiheum/equinox
sudo apt-get update && sudo apt-get install gtk2-engines-equinox
Then install all the four themes at once with the below command.
sudo apt-get install equinox-theme
That's it!, enjoy.