They are made from gold or bronze and are penannular, providing a slot that is thought to have been used for attaching them as earrings or as hair ornaments. Ireland was a centre of production in the British Isles though rings were made and used across the continent, notably by the Unetice culture of central Europe.
External link
Lock rings found at Great Orme in Wales (http://www.gtj.org.uk/item.php?lang=en&id=25863&t=1)
Some weapons have this built into the barrel in the form of an adjustable lockring like the FAMAS F1 or like the SIG 550, Steyr AUG or HK G3A4 that utilize a non-adjustable lockring (usually silver in color).
This type can also be found on the barrel or flash suppressor, which acts as a fixed position o-ring to hold the grenade in the correct place for launching.
We are often in earlier and or later than the aforementioned hours so if we hear the phone ring we will answer it.