Elite PE Foam case with CART has all of the external features of the patented Standard Porter Case ELITE. On the inside, we have added 4 layers of medium density gray foam 1 1/4" thick with a convoluted gray foam sheet in the lid. This configuration allows the traveling professional to easily customize the interior to transport, protect, and organize expensive delicate items. It can then be easily be rolled "on board" and placed under most seats or in the overhead compartment while checking through your other items. After your trip, the patented CART feature instantly appears to help you carry up to 200 pounds of extra gear on top.