Many of the Swiss Army knives from Wenger include a small key ring. It is about 12mm wide (1/2 inch) on larger knives, and 8mm wide (3/8 inch) on the smaller knives. The key ring replaced the earlier bail/shackle.
In the 1990's and 2000's, Wenger included a key chain on some models. It is about 30mm (1 1/4") long, with a key ring at the end.
Uses: You can use the key chain or keyring to attach your pocket knife
to a couple of keys, to a larger key ring, or to just about anything else.
Some people remove the key ring, or even file off its support. Although handy, it does sometimes snag on the inside of pockets.