Containers

Sizes, and one regulatory boundary

Updated October 2026

On this page8

The range The small end The middle The large end Headspace is not a cosmetic choice And the 30 mL limit is below everything Standardize for the cabinet, not the catalog References

A narrow range, and the regulation’s number is below the bottom of it.

The range

Fifty-five milliliters at the small end to 946 at the large, across 29 containers. That is a collection and display range rather than a production one, which matches what this shelf is for.

The small end

55 to 120 mL suits a single insect, a small wet specimen or a replica egg. It is also the size most often wanted in quantity for a series, so standardizing here pays off across a cabinet.

The middle

A few hundred milliliters is a small skull, a larger wet specimen or a group. The neck becomes the constraint before the volume does, because the specimen has to go in without touching the walls.

The large end

Up to 946 mL, which is a quart jar. At that size weight and breakage are real, and a shelf or cabinet designed for it matters as much as the jar does.

Headspace is not a cosmetic choice

A jar must not be liquid-full at 55 C under 49 CFR 173.4, and quite apart from that a fluid-filled jar with no headspace will push past its liner as it warms. Leave room deliberately.

And the 30 mL limit is below everything

For the small-quantity shipping route the inner receptacle can hold no more than 30 mL, and our smallest is 55. So no size on this shelf makes that route available, and choosing a smaller jar here does not help.

Standardize for the cabinet, not the catalog

A collection in one jar size and one closure is easier to store, easier to label and easier to maintain. With 7 containers each on 58-400 and 53-400, those are the two obvious finishes to build on.

References

49 CFR 173.4, Small quantities for highway and rail. Class 3 and other listed materials are not subject to other requirements where the inner receptacle holds no more than 30 mL of liquid, is not liquid-full at 55 C, is glass, earthenware, metal or plastic of at least 0.2 mm, has any removable closure held securely with wire, tape or other positive means, and is packed with non-reactive absorbent able to take the entire contents inside a strong outer packaging, the whole demonstrated by prototype testing. law.cornell.edu

49 CFR 173.4b, De minimis exceptions, which take listed Packing Group II and III materials out of the definition of a hazardous material at 1 mL per inner receptacle for liquids, subject to five specified 1.8 m drops and a compressive load. law.cornell.edu

Written from federal statute and regulation, not from a collection room. Wildlife law is federal, state and sometimes tribal at once, and the Lacey Act makes a state or foreign violation a federal matter. Nothing here is advice on a particular specimen, and the permit questions belong to the Fish and Wildlife Service.