The words not restricted together with the special provision number.
A dry shipper travels as not restricted under Special Provision A152 of the IATA Dangerous Goods Regulations, provided the packaging cannot build pressure or release nitrogen in any orientation. The annotation on the air waybill is what tells the carrier that, and its absence is what causes consignments to be held.
Packing Instruction 650 of the same regulations governs the biological samples inside, where those are classified as UN 3373 Category B. It applies to the samples, not to the nitrogen holding them cold.
Those two provisions are constantly conflated, including across a good deal of supplier literature. A dry shipper is not exempt from Packing Instruction 650, and Packing Instruction 650 was never about the nitrogen. Getting it wrong in either direction produces the same result at the airport.
