The World's First Mid-Sized Modular Tower with Exterior Expandability. The MasterCase 5 allows you to have absolute control over how your case looks and functions, and that means giving you the option to adjust the exterior structure and aesthetic via a range of replacement panels and doors. Each choice changes the look and feel of the case, but also the flexibility of the interior layout. Leveraging our unique clip-and-click panel design, FreeForm lets users vertically adjust or entirely remove drive cages, allowing for multiple system configurations. The MasterCase Pro 5 - Make Of It What You Will.