You could have downloaded FinderFileSizes 1.7.1 for Mac from our application library for free. This program's bundle is identified as com.corefault.FinderFileSizes. The most popular version of the program is 1.7. The FinderFileSizes installer is commonly called ffs_1.7.1.dmg. The actual developer of this free Mac application is Daniel Kagemann. The application lies within System Tools, more precisely File Managers.
From the developer:
FinderFileSizes shows the size of all selected files and folders currently selected in the frontmost finder window. The process runs in background without harming the Finder.
The information can be displayed automatically in the system menu bar or with the shortcut ctrl+i as notification on the screen.
You may want to check out more Mac applications, such as Mac ScanAndSweep, NotLight or Dock Changer, which might be similar to FinderFileSizes.