Brand: Automotive Racing Products (ARP)
These high-strength (180,000 psi) chrome moly nuts are a perfect match for ARP 5/16-24 Black Oxide Bolt 5-Packs (sold separately).
The 5/16-24 UNF (fine thread) nuts take a 3/8" 12-point socket, but they have a full 9/16" OD bearing surface, just like the matching ARP 741 Series bolts. Head measures 0.348" high overall. The black oxide finish looks great and is easy to paint if desired. Pack of 2 nuts.