The Zero boxes present a "bento-style stacking system," thanks to which the need for lids is minimized as the bottom of one container serves as the lid for another. While consumers have to pay a small fee for the reusable fast food packaging, they are reimbursed upon their next order when the containers are returned to the delivery service provider. This creates a handy loyalty scheme.
The packaging is transferable between restaurants—of course, properly sanitized after each use.
Image Credit: PriestmanGoode, Carolyn Brown