Which 38-400 Do You Need?


At Reliable Caps, we have a wide selection of closures, and each neck finish option can fit a range of bottles and applications. Our 38-400 is a popular and versatile choice, but there are multiple options of this cap, each built for a different situation. This guide will help you determine which 38-400 closure is right for you, depending on your application needs.

Questions to Ask About Your Closure

When you’re considering which configuration to choose in the 38-400 closure line, these questions can help guide your decision-making process: 

  • Do you need child-resistant packaging?
  • Is a heavy-duty closure required?
  • Do you need a larger thread profile?

Depending on the answer to each of these questions, you can eliminate the specialty configurations or build the specific closure you need for your packaging.


Does Your Product Require Child-Resistant Packaging?

If yes, the 38-400 CR is your best choice. This closure is a push-down-and-turn child-resistant closure with a modified buttress thread profile, and it’s built to meet CRC compliance requirements. 

These closures are usually a great choice for:

If child-resistant packaging isn't part of your requirements, keep going to figure out what other features you may need.



Do You Need a Heavy-Duty Closure?

Some applications need more durability than a standard cap can offer. If you're working with aggressive contents, demanding storage or shipping conditions, or your product needs to pass D.O.T. drop testing, the 38-400 HW is likely your best choice. Thicker and stronger than a standard closure, the 38-400 uses the same modified buttress thread profile, and can be molded with copolymer PP for greater durability.



Is a Larger Thread Profile Needed?

If your bottle's neck finish runs on the low end of the 38-400 spec, which is pretty common with older-tooled HDPE bottles, a standard cap might not seat the way you'd expect. The 38-400 Unscrewing Core Molded closure has a larger modified buttress thread profile designed to handle that variation. If you've had fit or seal issues with other closures on those bottles, this is likely the fix.



For Most Applications: The Strip Molded 38-400

If none of the above situations apply, the 38-400 Strip Molded is probably what you need. These caps use a standard thread profile and have a larger diameter liner wad than the unscrewing core molded options above, which works especially well for PET bottles with a narrower landing area. The strip molded 38-400 is great for applications including: 

For a wide range standard applications, this cap is a great choice!



Still Have Questions?

At Reliable Caps, we’ve been working with customers on closure selection for over 60 years and can help you figure out the best option for your closure needs. To discuss your selection or get a sample before ordering, reach out to our team today.

Contact Reliable Caps