Akvis SmartMask for Mac

From AKVIS:

AKVIS SmartMask plugin is an efficient masking tool that saves you time on complex selections and is fun to use. The idea is so simple that you will feel like a child in drawing classes: there are two pencils (red and blue); you draw a line with the blue pencil inside the object you want to select (for example, yourself in a group photo), and with the red pencil - some lines outside the object, to define the areas that should be cut out (other guys in the photo).