Thermoformed locking assembly comprising a first web portion including locking lug having lug undercut defining a cantilevered lug ledge having lug engaging surface, second web portion including locking recess having recess undercut defining an opposing recess ledge having recess engaging surface and a lug stop opposite the recess undercut. Locking recess configured to receive locking lug and lug stop configured to position locking lug in locking recess with the lug engaging surface in engagement with the recess engaging surface when first web portion is moved towards second web portion.