Sparex source: https://us.sparex.com/half-jam-nut-thread-size-1-2-unf-din-or-standard-no-din-439b-1837.html Product: Half Jam Nut, Thread Size: 1/2'' UNF (din Or Standard No. Din 439b) - Sparex S.1837 SKU: S.1837 Listing note: Tensile strength: 8.8 Detail enrichment pending: OEM cross references, fitment, catalog pages, and full specifications.