UN packagings are fabricated and tested to specific levels of performance. These tests allow a manufacturer to mark the packaging with the appropriate testing criteria (eg: packing group, maximum gross weight, contents). Often, users innocently alter the integrity of the package by adding accessories (eg: a plastic liner) or by replacing accessories with different components (eg: closure ring, gasket) in which case, the certification of the package can be voided if not re-tested for qualification. “A different packaging” is defined in CFR49 178.601(c)(4) as a packaging that differs from a previously produced packaging in structural design, size, material of construction, wall thickness or manner of construction. Further design qualification testing is not required if the alterations to the packaging do not constitute “a different packaging.” Also, Closure Instructions are packaging specific and must be used only for the packagings as designated.