USPS Packaging Instruction 10B

Excepted Quantity Provision

Some types of hazardous materials, as permitted in 337 and 49 CFR 173.4a, may be prepared for mailing using the excepted quantity provision. The excepted quantity provision, although applicable to international shipments by commercial shippers, is limited to domestic mail, and its use is prohibited in international and APO/FPO/DPO mail.

Proper Shipping Name and ID Number

Prototype Testing Requirement

Mailability

Required Packaging

Inner (Primary) Receptacle
Intermediate (Secondary) Packaging
Absorbent and Cushioning Material

For liquids, intermediate containers must contain sufficient absorbent material that:

Outer Packaging
Markings
Documentation