Typically required if thread has stripped or damaged.
Genuine NAMI Electric factory spare.
Notes:
This is the newer type, Michael Sha references: "The one big bearing cover will be only used for the latest version, the original version without the space machined in the head tube could fit two small bearing cover, one in the bottom and one in the top. Fluid Freeride reference the newer type as Single Nut (version) which as Michael mentioned negates the need for separate locking nut of the older version and is backward compatible. Observe the internal thread.