Chain mail

Finger-jointed mesh: the rings are simply pressed together, without fastening. They are "butted" together. This method is simpler to produce, less costly, but considerably less resistant. It is often found in modern, inexpensive chainmail (often for GN or cosplay).
Riveted mesh: each ring is pierced and closed by a small metal rivet, making it much stronger. This technique requires more advanced know-how, but offers far greater durability. Rings can be flat or round, with round or wedge-shaped rivets.
Riveted mesh is by far the most historic. It can be found :
. As far back as Antiquity (the Celts, then the Romans with the lorica hamata),
. Almost systematically in the European Middle Ages, particularly among knights from the XIIᵉ century onwards,
. In many Eastern cultures too (Seljuks, Persians, etc.).
Some medieval coats of mail combined riveted and solid (unopened) rings to optimize strength and economy. A fully butted chain mail would have been a nonsense in real combat: it would have yielded too easily to sharp blows and tension.