Bottle Neck Finishes: 18/410, 20/410, 24/410 and 28/410 Explained

Every bottle we mould is defined by its neck before anything else. The neck is the only part of the container that has to interface with a component made somewhere else, to a tolerance measured in tenths of a millimetre.

Below is how the four finishes we hold in stock are used, and how to choose between them.

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What the Two Numbers Mean

Take 24/410. The 24 is the nominal outside diameter of the neck in millimetres. The 410 is the thread standard: a single-start thread with a defined pitch and depth. Two bottles can both be “24 mm” and still take different closures if the thread differs — which is why the second number is the one to quote.

Why the Same Neck From Two Suppliers May Not Fit

Thread dimensions have a tolerance band, and moulds wear. A pump that clicks onto one 24/410 bottle may feel tight on another. This is normal and is why we test pumps on our own bottles rather than trusting the drawing alone.

If you are buying bottles and pumps from different suppliers, ask both for the neck drawing and compare the thread callout, not just the diameter.

Matching a Closure to a Product

Viscous products — lotions, creams, gels — need a pump with a dip tube that reaches the bottom corner. Thin products suit a disc-top or flip-top. Oils and serums usually take a dropper at 18/410. Mist sprayers at 20/410 and 24/410 are for fragrances and toners.

Where Neck Specs Go Wrong

The failures are consistent, and all of them are visible on a sample within a week.

Mixing 410 and 415 Threads

Both are 24 mm, both accept a 24 mm pump, and only one seals. A 24/415 bottle with a 24/410 pump threads on by hand and leaks on a filling line at 2 bar. Ask the closure supplier for the thread code, not just the diameter.

Measuring the Neck on a Photo

Neck finish cannot be read from a product photo — the thread height is 2.5 mm on a 410 and 5 mm on a 415. Send a bottle, or a caliper reading of T, E and H dimensions.

Assuming a Neck Is Standard Because the Bottle Is

A 500 ml bottle shape is often available with two different necks from the same mould family. Confirm the neck on the drawing, not on the model name.

What to Send in a Brief

The complete neck code (e.g. 24/410), the closure you intend to use, and one sample if you have it. With those three we confirm fit before quoting, instead of after the first container.

If you are choosing the neck as well, 24/410 covers most pumps; 28/410 for 500-750 ml; 18/410 and 20/410 for droppers and mist sprayers.

Questions We Get on This

Is 24/410 the same as 24/415?

No. Both are 24 mm necks, but the thread differs and closures are not interchangeable. Quote the full number, including the thread, on every purchase order.

Can you make a bottle with a neck you do not stock?

Yes, with a new neck insert. It is a modification to an existing mould rather than a new mould, typically USD 300–800 and 7–10 days.

How do I measure a neck without a drawing?

Measure the outside diameter across the threads with a caliper, then send a photo of the closure's thread. We identify the finish from those two.

Do you supply closures separately?

Yes — pumps, sprayers and caps at 1,000 pcs MOQ, whether or not you buy the bottle from us.

What does 24/410 mean?

24 mm neck diameter with a 410 thread profile. The 410 is the thread height, not the diameter.

Will a 28/410 cap fit a 24/410 bottle?

No. The diameter differs by 4 mm; the closure will not seal.

Can you match a neck from a sample I send?

Yes — we measure T, E and H and confirm against the mould drawing.