A few Leatherman tools have a lanyard ring that folds out, and allows the tool to be attached to a lanyard or key ring.
Fold out the lanyard ring if you want to attach a large Leatherman tool to a lanyard, or just a temporary piece of twine (e.g. when you are working on a roof or ladder).
Some small Leatherman tools have a key ring that serves the same function.
Many Leatherman knives and newer tools have a carabiner that is even more convenient for attaching the tool.
No Victorinox or Wenger Swiss Army knives have a lanyard ring, but most have a key ring that serves a similar function.