Screw Caps

MIRON Violetglass stocks a wide range of screw caps which can be used to perfectly seal a large variety of our bottles, such as glass water bottles, glass syrup bottles or smaller glass dropper bottles. Depending on the functionalities of your product as well as the look and feel you want to achieve, you can choose between ripped caps and smooth caps. The screw caps are available with an integrated insert as an option or with a violet sealing element. Inserts include vertical droppers (also called “euro” droppers in the US), reducers, orifice reducers, pourers, and roll-ons. The right choice hereby depends on your premium products and the way it shall pour, drip or flow out of our bottles.

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Tamper-evident is designed as an integral safety band that offers protection against tampering. To open the product, the consumer automatically detaches the cap from its safety band - this is happening because the band is attached to the bottle or jar around the closure perimeter.

Series II, III, IIID

The number in the series indicates the shape of the cap and the tamper-evident element of the screw caps. For instance, II suggests that the closure has a tampered evident ring attached to the closure, and because the cap is made of only one material/mold, it has 4-6 ridges on the side. Series III has a thicker rim and features a more luxurious tampered evidence element. This series is made from multiple molds, which means that a different system of tempered proof is used consisting of retention fingers instead of ridges on the tear strip, making it less easy to manipulate. Series IIID, on the other hand, is entirely the same as III except for the fact that it has a smooth surface.


The acronym ROPP means Roll on Pilfer Proof. These types of caps are tamper-evident, in which on first opening, the tamper-evident band breaks. Not only will it protect your natural products from being tampered, but it also prevents spills of content.

Let’s talk about threads

...But what exactly are threads?

Simply put, threads are the protruding lines curved around the neck of the bottle. They ensure that the matching closure will have a tight fit to protect your natural ingredients from being tampered with or from leakage. The threads size depends on the size of the bottle neck as well as our range of closures. Our bottles and jars as well as the corresponding closures must have matching threads. If in doubt, it is always advisable to contact the sales department.

STD and DIN18

STD is a DIN size. DIN is the industry standard for dropper bottles in Europe, and DIN18 is the German-based norm. It refers to the standard size of the neck, height, and diameter. Screw caps with a DIN18 threaded closure go hand in hand with any Orion dropper bottle up to 100ml (3 ½- oz) that features the DIN18 thread and a tamper-evident transferring. The right choice to ensure product safety.


GPI and GCMI are the US norm of neck finishes and are followed by two numbers written like this: 22/400*. The first number indicates the neck finish diameter and is measured across the outside of the bottle’s threads. The second number refers to the height and thread style. Meaning, the number of threads turns around the neck. Simply match the GPI or GCMI code listed in the product description to purchase the corresponding items.
* Please note that if a bottle has an additional ring in the neck, this may affect the choice of matching closure. For more details, please get in touch with your representative.


PP is also known as polypropylene and falls under the plastic identification code number 5. The material is easily produced and has a high degree of purity. It comes with a range of benefits, so is it difficult to break, lightweight, easily and 100% recyclable. Due to its properties, PP is suitable for various applications, including food, cosmetic, and natural healing product packaging. Urea formaldehyde molding material (UF) is also known as amino plastic. This type of material has become a common component of closure applications. The UF resins are noted for their high strength and rigidity.


The violet sealing element in the lid is made of PHAN, a three-layer laminated product consisting of two layers of solid PET film on the outside and a layer of foamed EPE on the inside. It is the foamed core in the center that provides the resilience needed for an airtight seal.

Ribbed, Matt, and Smooth

Here we refer to the tangible elements of the closure. Where ribbed means that the closure has a pattern of raised bands, matt refers to a surface without a shine, and smooth means having an even surface free from perceptible patterns, ribbing, or indentations.

At MIRON Violetglass we ensure that our closures always fit the corresponding bottles and jars. However, it can sometimes be a bit of a challenge to find the right closure which complements the needs of your natural ingredients. We are always happy to answer any questions you may have and to become a part of your products journey.

For more information about threads, visit our Neck Finishes Explained guide.