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How to Select Bottle Cap and Neck Size?

-Monday, January 19, 2015

“BRI”ef: 106 - Packaging Options Direct – Guide to Container Neck Finishes

At Packaging Options Direct, we know choosing the right container can be tricky with all the different options on the market. From glass to plastic, bottles to jars, there are so many choices available; and in my previous “BRI”ef’s I’ve given some information to help you choose the best packaging for your needs. However, once you’ve decided on your container, you also have to choose the right style of closure, and you want to make sure it’s the right fit. As an Account Coordinator, I find that one of the questions I hear the most is “How do I know which closure to buy?” So I offer you this “BRIef guide to selecting the correct closures for your needs.

Selecting Cap and Neck Sizes

The first step is understanding what size closure will work with the jar or bottle you have selected. On our website, we list each container’s thread finish in a couple different places on the product page. One of those places is at the top of the page underneath the main product description; usually listed as two numbers with a hyphen (example: 28-400). We also have two rows in the product table that provide this information. One row called “Neck Finish” and the other called “Neck Height Dimension”. But what do these numbers mean?

Cap and Neck Sizes Example

When looking at a bottle or jar, the neck finish (or the “28” in the example above) refers to the outer diameter of the container opening from the outer thread to the outer thread (the thread being the spiral bump that holds the cap on the bottles). When referring to lids, this same number is used to denote the nominal diameter across the inside of the cap, but without the thread included, just the inner wall of the cap to the inner wall on the opposite side.

The second number provides much more information. It refers to the standard dimensions as determined by industry trade groups; either GPI (Glass Packaging Institute standard) thread finish for glass bottles (as in the “400” in the example above) or SPI (Society of Plastics Industry) for plastic bottles. These dimensions and features include the height of the cap, and the style of threads on the cap or container.

Cap and Neck Size Dimensions

Two of the more common thread styles are continuous thread, which is a finish that has one thread that spirals downward toward the shoulder of the container; and a lug thread, which is a finish of three or four separate threads.

Thread Styles

Other common container finishes are: cork finish, a smooth finish in which a cork fits; swing-type, which are lids that have hinges much like our Kilner jars; and crimp closures which require special machines or tools to apply, much like beer bottle crown caps.

Cap and Neck Finishes

Once you have an understanding on how to select the right size closure, you have to decide on the type of closure you want. Do you want a plain continuous thread closure, or something with more finesse for dispensing? Atomizers (also known as fine mist sprayers), lotion or treatment pumps, droppers, spout closures, flip-top (also known as snap-top or snap-type), press tops (also known as disc lids), turrets (also known as flip-spout lids), and flapper lids can all give your container a more user friendly edge. Lids with a plastisol liner can give you the vacuum seal functionality of a canning lid, like those often found in the kitchen or canning section of your local retail or grocery store.

Types of Dispensing Lids

As always, I am happy to help any time our valued customers have questions. Please feel free to call us at (855) 754-3728 if you should ever need assistance with choosing the correct closure for your specific needs.

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