Complies fully with US Postal Service, DOT and IATA regulations for transport of clinical and diagnostic specimens (UN3373) by air or ground; Domestic Mail Manual Part 8.6; Title 49 CFR, Part 173, 199; and IATA Packing Instruction 650. Includes all required secondary and outer packaging components. Users provide only leak-proof specimen containers (primary receptacles), such as tubes, vials, cups, etc. Accommodates any size and quantity of specimen containers that fit inside the flexible secondary envelope with required absorbent material. Maximum capacity is 300 ml or less.