18mm

screw metal cap, also known as a screw-on metal cap or a metal closure, is a type of closure commonly used in packaging. It consists of a metal cap with internal threads that Screw onto the external threads of a container or bottle to secure its contents. Screw metal caps are often used in industries such as food and beverage, cosmetics, pharmaceuticals, and household products.
The caps can be lined with various materials, such as plastic or foam, to provide additional protection and prevent leakage or contamination of the packaged product.

Rubber septa, also known as rubber stoppers or closures, are commonly used in laboratories as a sealing material for vials, bottles, and other containers. A septum (plural: septa) is a thin piece of rubber or elastomeric material that is designed to provide an airtight or liquid-tight seal when inserted into the opening of a container.
Rubber septa are typically made from a variety of elastomeric materials, such as natural rubber or synthetic polymers like silicone or butyl rubber.
These materials are chosen for their flexibility, chemical resistance, and ability to form a tight seal.

18mm screw top headspace borosilicate glass vial refers to a specific type of vial commonly used in gas chromatography (GC) analysis for the analysis of volatile compounds in samples.
It’s important to note that specific details of the vial, such as volume, thread type, and cap design, can vary between manufacturers and suppliers. Therefore, it’s recommended to consult the specific product specifications or contact the supplier for precise information about the 18mm screw top headspace borosilicate glass vials you are considering.