GUK5 Budget Locknut With Nylon Insert (KM5-Nyloc)
GUK series = KM Series lock nuts with a nylon insert (Nyloc style)
GUK lock nuts are used to locate bearings onto a shaft. They have metric threads and four equally spaced slots located around their circumference to accommodate a spanner. They should be locked by a lock washer to prevent unintentional loosening. GUK lock nuts can be reused. provided they are not damaged.