If you have ever sourced plastic bottles, lotion pumps, sprayers, or caps, you have probably seen specifications such as 18/410, 20/410, 24/410, and 28/410.

These numbers describe the bottle neck finish and are important when matching a bottle with a compatible closure or dispensing system.

For packaging buyers, understanding neck finish sizes can help avoid one of the most common sourcing problems: ordering a bottle and closure that do not fit or function correctly together.

In this guide, we explain what 20/410, 24/410, 28/410, and other common neck finishes mean, how they relate to pumps and sprayers, and what you should check before placing a packaging order.

What Is a Bottle Neck Finish?

The neck finish is the part of a bottle around the opening where a cap, pump, sprayer, dropper, or other closure is attached.

It includes important dimensions and design features such as the neck diameter and thread configuration.

Common neck finish specifications used in packaging include:

• 18/410
• 20/410
• 24/410
• 28/410
• 28/400
• 33/400

Different packaging categories may use other neck finishes as well.

What Does 24/410 Mean?

Let’s use 24/410 as an example.

The first number, 24, refers to the approximate nominal diameter of the bottle neck in millimeters.

The second number, 410, identifies the thread style or neck finish specification.

Therefore, a bottle described as 24/410 is designed with a nominal 24 mm neck finish using the corresponding 410 thread configuration.

A compatible closure would also normally be specified as 24/410.

What Does the /410 Mean?

The number after the slash refers to the neck finish or thread specification rather than the diameter.

This is important because two closures with the same nominal diameter may have different thread configurations.

For example:

• 28/400
• 28/410

Both use the same nominal neck diameter, but they are different neck finishes and should not automatically be treated as interchangeable.

When sourcing packaging, both parts of the specification should match the intended bottle and closure system.

Common Bottle Neck Finish Sizes

Neck Finish	Common Packaging Applications	Common Closure Options
18/410	Small bottles, cosmetic and personal care packaging	Droppers, sprayers, screw caps
20/410	Skincare, cosmetic and small personal care bottles	Fine mist sprayers, lotion pumps, caps
24/410	Personal care, hair care and body care bottles	Lotion pumps, sprayers, disc top caps, flip top caps
28/410	Larger personal care and household bottles	Lotion pumps, trigger sprayers, caps

These are common examples rather than universal rules. The available closure options depend on the specific bottle, closure design, product, and supplier.

18/410: Common for Smaller Bottles

18/410 is frequently found on smaller packaging formats.

For example, small PET bottles and other containers used for oils, serums, personal care products, and similar applications may use an 18/410 neck finish.

Depending on the bottle design, compatible closures may include:

• Dropper assemblies
• Fine mist sprayers
• Screw caps
• Other specialty closures

If you are sourcing a dropper bottle, it is important to confirm both the bottle neck finish and the complete dropper assembly rather than relying only on the nominal diameter.

20/410: Popular for Skincare and Personal Care

20/410 is commonly used for smaller cosmetic, skincare, and personal care bottles.

It can be paired with suitable dispensing components such as:

• Fine mist sprayers
• Lotion pumps
• Screw caps
• Other dispensing closures

For products such as facial sprays, hair products, lotions, or personal care formulations, 20/410 can provide a compact bottle-and-closure combination.

24/410: A Versatile Packaging Neck Finish

24/410 is widely used across personal care packaging.

Common applications include:

• Shampoo
• Conditioner
• Body wash
• Lotion
• Hand soap
• Hair care products
• Personal care sprays

One advantage of this size is the broad range of dispensing options available for many packaging designs.

A 24/410 bottle may be paired with a lotion pump, fine mist sprayer, disc top cap, flip top cap, or screw cap depending on the product and bottle design.

28/410: Common for Larger Bottles and Household Products

28/410 is commonly found on larger bottles, including packaging used for personal care and household products.

Potential dispensing options include:

• Trigger sprayers
• Lotion pumps
• Dispensing pumps
• Screw caps
• Other compatible closures

For household cleaners, larger-volume personal care products, and similar applications, a 28/410 neck can provide access to a wide range of dispensing systems.

Does a 24/410 Pump Fit Every 24/410 Bottle?

Not necessarily.

A matching neck finish is an important starting point, but it does not guarantee that every pump will work correctly with every bottle.

The complete packaging system should also consider:

• Thread engagement
• Gasket or sealing requirements
• Bottle neck dimensions and tolerances
• Dip tube length
• Pump output
• Formula viscosity
• Product compatibility
• Leak resistance

This is why packaging samples and compatibility testing are important before placing a large production order.

Why Is Dip Tube Length Important?

When using lotion pumps, fine mist sprayers, trigger sprayers, and other dispensing systems, the dip tube must be appropriate for the bottle.

If the dip tube is too short, it may not reach enough of the product at the bottom of the bottle.

If it is too long, it may bend excessively or interfere with dispensing performance.

When requesting pumps or sprayers, provide the bottle specifications or purchase the bottle and dispensing closure as a matched packaging set whenever possible.

Neck Finish vs. Closure Size

Packaging buyers sometimes assume that a closure labeled 24 mm will automatically fit any bottle with an approximately 24 mm opening.

This is not a reliable way to select packaging components.

A proper specification should include the complete neck finish, such as 24/410, rather than only the nominal diameter.

The bottle and closure should then be tested together to confirm actual fit and performance.

What About 400 vs. 410 Neck Finishes?

You may also see specifications such as 28/400 and 28/410.

The first number indicates the same nominal neck diameter, but the second number identifies a different neck finish specification.

As a result, a 28/400 closure and a 28/410 closure should not automatically be assumed to fit the same bottle correctly.

Always confirm the complete specification when ordering replacement caps, pumps, or sprayers.

How to Choose a Bottle and Closure Together

Instead of selecting the bottle and closure independently, consider them as one complete packaging system.

Before requesting a quotation, prepare the following information:

• Product: What will be filled into the bottle?
• Capacity: What bottle volume is required?
• Bottle Material: PET, HDPE, PP, PETG, or another material?
• Neck Finish: For example, 20/410, 24/410, or 28/410
• Closure: Pump, sprayer, trigger, dropper, or cap?
• Dispensing Output: How much product should be dispensed per actuation?
• Formula Viscosity: Is the product thin, medium, or thick?
• Color: Standard or custom color?
• Decoration: Printing, labels, or other decoration?
• Quantity: What is the estimated order quantity?

If you already have a bottle or closure that you want to match, providing physical samples or detailed specifications can make component matching more reliable.

Common Bottle and Closure Combinations

Application	Possible Bottle	Possible Closure
Facial Mist	20/410 PET Bottle	20/410 Fine Mist Sprayer
Body Lotion	24/410 PET or HDPE Bottle	24/410 Lotion Pump
Shampoo	24/410 Plastic Bottle	24/410 Disc Top or Flip Top Cap
Household Cleaner	28/410 Plastic Bottle	28/410 Trigger Sprayer
Oil or Serum	18/410 Small Bottle	18/410 Dropper or Cap

These examples illustrate common combinations only. Actual compatibility should always be confirmed for the specific components and product.

Custom Bottles, Pumps and Closures from UNALILIA

UNALILIA provides custom packaging solutions for skincare, hair care, body care, cosmetics, household cleaning, food, supplements, and other applications.

Packaging options include:

• Plastic bottles
• Plastic jars
• Dropper bottles
• Lotion pumps
• Fine mist sprayers
• Trigger sprayers
• Disc top caps
• Flip top caps
• Screw caps
• Labels and stickers

Different materials, capacities, neck finishes, colors, dispensing systems, and decoration options can be discussed according to your packaging requirements.

Request a Bottle and Closure Quote

Not sure which neck finish or closure is right for your product?

Send UNALILIA your product type, required capacity, bottle material, preferred bottle shape, neck finish, dispensing requirements, color, decoration, and estimated quantity.

If you already have a bottle, pump, sprayer, or cap that you need to match, send us the specifications or reference images so suitable options can be discussed.

Contact UNALILIA today to discuss your custom bottle and closure project and request a quote.

Frequently Asked Questions About Bottle Neck Finishes

What does 24/410 mean on a bottle?

24/410 describes a bottle neck finish. The 24 refers to the nominal neck diameter in millimeters, while 410 identifies the thread or neck finish specification used to match compatible closures.

What is the difference between 20/410 and 24/410?

The primary difference is the nominal neck diameter. A 20/410 bottle uses a smaller neck finish than a 24/410 bottle, and each requires a closure designed for the corresponding specification.

Will a 24/410 pump fit a 24/410 bottle?

A matching 24/410 specification is an important starting point, but actual compatibility should still be confirmed. Thread tolerances, gasket design, dip tube length, formula, and dispensing performance can affect the complete package.

What neck size is commonly used for lotion pumps?

Lotion pumps are available in several neck finishes, including 20/410, 24/410, and 28/410 depending on the bottle and application. The correct size should match the bottle neck finish and product requirements.

What neck size is commonly used for trigger sprayers?

28/410 is a common neck finish for many trigger sprayer applications, particularly household and cleaning products. Other specifications are also available depending on the packaging system.

Are 28/400 and 28/410 interchangeable?

They should not automatically be considered interchangeable. Although both have the same nominal diameter, they use different neck finish specifications. The bottle and closure should be matched and tested together.