Guide to Bottle Neck Finishes (and Why They Matter)

When it comes to packaging liquids, creams, serums, or sprays, many business owners overlook one of the most important details: the neck finish. This small set of numbers  -  like 20-400, 28-410, or 89-400  -  determines what closure, cap, sprayer, or pump will fit your container. At Liquid Bottles, understanding these neck finishes helps you pair bottles with the right closures every time and avoid leaks, compatibility issues, and customer frustration.

What Is a Neck Finish?

A neck finish refers to the diameter and thread style on the opening of a bottle or jar. It’s how a closure  -  like a cap, pump, or dropper  -  mechanically latches onto a container. A typical neck finish code has two parts:

• First number – the outside thread diameter in millimeters (e.g., 20, 28, 89).

• Second number – the thread style or height (e.g., 400, 410, 415). 

For example:

• 20-400 = 20 mm diameter with a standard "400" thread style

• 28-410 = 28 mm diameter with a deeper "410" thread style

These neck finishes must match exactly between bottle and closure to ensure a secure seal and proper fit.

Why Neck Finishes Matter

Here’s why neck finishes are more than just technical codes:

1. Closure Compatibility

Caps, sprayers, pumps, & droppers are all sized to match specific neck finishes. Ordering a bottle with a 24‑410 neck but a closure designed for 24‑400 threads simply won’t work -  even though the numbers seem similar.

2. Product Performance

Different finishes affect how your product is dispensed:

• Smaller finishes (like 18‑400 or 20‑400) are ideal for droppers, fine mist sprayers, and serums.

• Mid‑size finishes (like 24‑410) fit lotions, shampoos, and treatment pumps

• Larger finishes (like 38‑400 and above) work with trigger sprayers or wide‑mouth caps.

Choosing the proper neck finish ensures your customers have a great experience with the dispensing style you intend.

3. Seal Integrity

Liquids and creams all require secure closure. The right neck finish ensures that the gasket inside the cap compresses properly against the bottle to keep air, moisture, and contaminants out.

4. Filling Efficiency

Neck size also affects how bottles are filled. Larger necks allow filling machines to load products more easily, reducing spillage and speeding up production, while smaller necks may require slower, more precise filling methods.

Common Neck Sizes You’ll Find at Liquid Bottles

Liquid Bottles offers a broad range of neck finish options across closures and containers. Some of the most popular ones include:

Each of these sizes has corresponding closures available  -  from dropper caps and fine mist sprayers to lotion pumps and trigger sprayers and even continuous thread and child resistant caps  -  making Liquid Bottles a one-stop source for your packaging.

Thread Style 400 vs. 410 vs. 415 — What’s the Difference?

The second number in the neck finish tells you how many thread turns are on the neck and affects how the closure fits:

• 400 – Standard single‑turn threads; works with basic screw caps.

• 410 – Deeper threads (about 1.5 turns), better for pumps & sprayers.

• 415 – Even deeper threads (≈2 turns), excellent for airtight seals on high‑end products. This is also the typical thread style needed for tamper-evident closures, making it ideal for products that require added safety and compliance.
  
  

This thread style affects how tight, fast, and secure the closure is — especially when paired with dosage pumps, precision sprayers, or tamper-evident caps.

Tips for Matching Bottles & Closures

One of the easiest ways to avoid compatibility issues is to use the built-in pairing tools on Liquid Bottles. Each bottle and closure product page is designed to help you confidently choose components that work together.

✔ Use the recommended matches on the product page
When viewing a bottle on LiquidBottles.com, scroll down the product page to find compatible closures that are specifically matched to that bottle’s neck finish.

✔ Check closure product pages too
Closure pages also list the bottles they are designed to fit, making it easy to confirm compatibility from either direction.

✔ Match the neck finish exactly
Even small differences in thread style (such as 400 vs. 410) matter. The recommended pairings eliminate guesswork and ensure a proper seal.

✔ Test before you buy
Liquid Bottles offers free samples so you can test whether a bottle and closure work with your specific product. Because every formulation is different  - from viscosity to oil content  - testing ensures your packaging performs perfectly before placing a larger order.

Bottom Line

Neck finishes may look like technical codes  -  but they’re the backbone of functional packaging. Getting them right ensures your product performs well, looks professional, and avoids costly mistakes like leaks or mis-sized components. Liquid Bottles makes it easy with hundreds of bottles and closures clearly listed by neck finish so you can confidently choose the best fit for your product needs.