they are 330gal totes. the totes have plastic panels on 2 sides of them when i get them. the panels snap onto the metal cage and are used for shipping labels and contents labels.they are about 2ft by 2ft. i cut them up and used them along with some aluinum angle to build the door. as long as you lap them so water won't run in ,it works fine. i try to use plastic or metal for everything so they will last.