When you build/rebuild your transfer case, you will more than likely need a new crush sleeve / spanring. This is a "torque to yield" part that compresses as you tighten the one big nut on the output shaft and is typically not reusable. Meaning if you are building your transfer case using the stainless or aluminum housings, you will more than likely need one of these to complete the built.
These are brand new factory original Getrag-supplied parts.
NOTE: These are sold individually. You only need 1 per transfer case.