Screw cap

It must be engineered to be cost-effective, to provide an effective seal (and barrier), to be compatible with the contents, to be easily opened by the consumer, often to be reclosable, and to comply with product, package, and environmental laws and regulations.

A tamper-evident band is a common tamper warning for screw caps of bottles, for example.

Screw caps' use as an alternative to cork for sealing wine bottles is gaining increasing support.

A screw cap is a metal cap that screws onto threads on the neck of a bottle, generally with a metal skirt down the neck to resemble the traditional wine capsule ("foil").

A layer of plastic (often PVDC), cork, rubber, or other soft material is used as wad to make a seal with the mouth of the bottle.