A Simple Guide for Small Businesses & Startups
Choosing the right closure isn't just about what looks good on the shelf. It's about functionality, product safety, and brand credibility. Whether you're packaging oils, skincare products, or liquids, your closure must fit your bottle's neck size and thread type.
1. Understanding Bottle Neck Sizes
Figure 1
The neck of a bottle is the top section that connects to the cap or closure. This part is critical because it determines which closures will fit.
Common neck sizes include:
-18mm – often used for essential oil bottles
- 20mm, 22mm, 24mm – common for personal care and cosmetic bottles
- 28mm and 33mm – often used for food, beverage, or pharmaceutical bottles
- 38mm+ – typically found on wide-mouth containers or jars
2. Understanding Thread Types
Threads are the spiral ridges molded into the neck of a bottle that allow closures to screw on securely. They ensure a proper seal and help prevent leaks or spills.
Our bottles neck size are 410, other common thread codes include:
- 400 – Standard continuous thread
- 410 – Slightly shorter thread height, often used for sprayers or pumps
- 415 – Narrower threads, typically for droppers
- 425 – Specialised threads used less frequently
If your closure’s thread type doesn’t match your bottle’s, it can result in leaks, loose fits, or a poor customer experience.
3. How Closure Sizes Are Labeled
Closures are labeled using a two-number format, such as 24-410.
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The first number (e.g., 24) refers to the diameter in millimeters.
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The second number (e.g., 410) refers to the thread style.
Examples:
- 18/410 → 18mm closure, 410 thread (common for mini sprayers, pumps, and droppers)
- 20/410 → 20mm closure, 410 thread (standard for screw caps, flip tops, and small pumps)
- 24/410 → 24mm closure, 410 thread (widely used for pumps and lotion dispensers)
- 28/410 → 28mm closure, 410 thread (typically used for larger pumps and trigger sprayers)
4. How to Match Closures with Bottles
To ensure a secure and professional fit:
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Measure the bottle neck’s outside diameter (use figure 1 as a guide)
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Identify the thread finish (e.g., 400, 410, 415)
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Choose a closure that matches both
If you’re unsure, email us at hello@brightpack.co.za or speak to one of our sales representatives, and we’ll gladly help you select the perfect closure for your bottle.
5. Common Mistakes to Avoid
- Pipettes only go with glass
- If the bottle has a 24mm neck, look for a 24mm closure (same with any other size neck - match the closure)
- Don't assume all 24mm lids will fit on 24mm neck
- Not all of our closures have a tamper evident ring. Please choose carefully, only the 24mm lids that have no tamper evident ring
Conclusion
Choosing the right closure comes down to matching the neck size/diameter and thread type. Getting it right ensures your product looks professional, functions properly, and delivers a great customer experience.
Need help choosing the right closure for your bottles? Our team can help you measure, match, and select the best option for your product line. Contact us per email us at hello@brightpack.co.za or contact one of our sales representatives or explore our full range of closures online.