UN Specification Packaging designed to solely contain dangerous goods. No inner packagings are required for a single packaging to perform its containment function; dangerous goods are therefore in direct contact with single UN spec packaging.
A Packaging system which includes inner packages contained within a single outer package. The outer package bears the UN rated packaging code; this code remains valid provided the package is assembled in the same way it was during testing - ie. the manufacturer's packing instruction must be followed.