The PC II Foam case with cart has all of the patented external features of the standard rolling porter case hard side carryon, but on the inside we have added customizable foam for the traveller who has specific items that must be protected. The interior consists of 4 layers of medium density gray foam 1.5" thick on the bottom and a sheet of convoluted foam in the lid. By making outlines of the articles to be protected on the surface of the foam layers and using a marker to trace and a craft knife or electric carving knife to remove the excess material, this case can be quickly customized to carry almost any specialty items that you need to protect. Roll on your best and check the rest. After your trip, the patented CART feature is instantly there to help you carry up to 200 pounds of extra gear on top.