The cylinder

What the gauge is describing

On this page11

Why a cylinder and not a ruler Why any orientation Why without compressing And why the abuse testing comes after Which is exactly a model kit The exclusion list tells you the reasoning A choking hazard and an obstruction hazard Which is why the magnet rule needed something extra Use it as a household tool That is a container decision this catalog can help with References

The cylinder is a model of something. That is why the test is shaped the way it is.

Why a cylinder and not a ruler

Because the hazard is three dimensional. A part can be long and still pass through, or short and wide and not. A single dimension would not describe it.

Why any orientation

Because a child does not present an object in its best aspect. The test allows for the worst one, which is how the object will actually arrive.

Why without compressing

Because the test is about the article as it exists, not as it could be made to be. A part squeezed through a gauge has not demonstrated anything.

And why the abuse testing comes after

Because the dangerous part is often not the one you handed over. It is the wheel that came off, the pin that worked loose, the magnet that separated from its mount.

Which is exactly a model kit

Scale models are made of parts designed to detach, and radio control models shed screws and bearings in normal use. The abuse round is the realistic one for this craft.

The exclusion list tells you the reasoning

Paper, fabric, yarn, fuzz, elastic and string are excluded because they are not rigid obstructions. The rule is about rigid objects of a particular size.

A choking hazard and an obstruction hazard

The section is about articles that present choking, aspiration or ingestion hazards. Three different things, and a part can be any of them.

Which is why the magnet rule needed something extra

A magnet that passes the size test can still cause an injury that has nothing to do with obstruction. The next section is about that.

Use it as a household tool

If a part fits entirely in the cylinder in any orientation, it belongs in a closed container rather than an open tray when there are small children in the house.

That is a container decision this catalog can help with

255 jars with lids, 31 child resistant closures, and 11 liners. None of it is required and all of it is available.

References

16 CFR 1501.4, test method: "Place the article, without compressing it, into the cylinder. If the article fits entirely within the cylinder, in any orientation, it fails to comply with the test procedure." Articles are then subjected to the use and abuse testing at 16 CFR 1500.51 and 1500.52, and any liberated component other than paper, fabric, yarn, fuzz, elastic and string is tested in the cylinder individually. The cylinder's dimensions are given in Figure 1 of the section rather than in its text. law.cornell.edu

The Davis Pack Supply catalog, measured 19 October 2026. The model parts and paint shelf is 1,136 rows: 646 containers and 490 closures. 5 mL to 2,000 mL with a median of 118; 25 containers at 15 mL or under, 84 at 30 or under, 183 at 60 or under, 336 at 120 or under, 522 at 250 or under. 351 PET, 117 glass, 100 HDPE, 78 PP. 376 bottles, 255 jars, 13 tubs and pails, 2 tubes. 175 clear, 141 white, 101 amber, 61 blue, 60 natural, 47 black. Closures: 288 continuous thread, 32 disc top, 31 child resistant, 26 spouted, 22 dome lids, 19 lug and twist, 14 phenolic, 13 spice caps, 11 liners and sealing discs, 10 flip top.

Written from 16 CFR 1501.4 and 16 CFR 1262, and from the catalog as it stood on 19 October 2026. No cylinder dimensions appear anywhere in this property, because the rule gives them in a figure rather than in its text. Whether a particular part or magnet passes either test is a determination about that article; we sell the container it is kept in. Whether a kit is a children's product is the four-factor test covered in the resin jewelry property.