I made these icons for the Adobe AIR app Snackr, because the icons that appear on the tray doesn't fit with the elementary-monochrome icon theme on tray.
To install it, extract the files from the zip and copy them. Then open a terminal and type the follow command:
On this Nautilus in root mode, go to /opt/Snackr/share/icons and paste the icons here.
Hope you like them!