A substrate container system comprises a container body having a bottom face, a front opening that enables passage of a substrate, and a back opening opposing the front opening, the back opening having a width smaller than that of the front opening; and a back cover that covers the back opening and establishes sealing engagement with the container body, wherein the back cover comprises a first gas inlet structure that bendingly extends under the bottom face of the container body upon assembly; wherein the first gas inlet structure comprises a downward facing gas intake port opposing the bottom face of the container body.