How deep (or shallow) your window is determines whether you can install, or mount, your blinds or shades as an inside or outside mount. "Minimum flush-mount depth" is the depth needed to mount the product fully into the recess of the window. This means that the product will appear flush with your wall and not stick out from the window frame.
The "minimum inside-mount depth" is the depth of flat mounting space needed to install the product inside your window. If your window does not meet the minimum inside-mount depth, the product cannot be installed as an inside mount. If your window meets the minimum inside-mount depth but not the minimum flush-mount depth, the product will not be flush with the window opening and wall and will protrude from the window frame. Before ordering blinds, be sure to check the depth requirements listed in the "Specifications and Installation" chart at the bottom of each product page.