Page 62 - Nate Fitch, Ron Funderburke "Climbing Knots"

Tying two overhand knots in line, on a sling or
cordellette, allows anchor builders to use the magic
X anchor more convincingly. It is now redundant, and
extension potential has been greatly limited.

redundant, self-adjusting, and strong system. However,
in Spectra or Dyneema slings, these load-limiting
knots can be difficult to untie after sustained cyclical
loads, like the kinds of loads applied by a toprope.

Using the Rope for Anchoring 49