5513-100 5/16 Inches-18 Stud to Post Conversion (50 Pairs) - Converts stud to post positive and negative. Lead standard post with steel insert for durability, the Nut features a nylon locking insert to prevent slippage or loosening. Post size is Per SAE J537, 13/16 Inches flats. Converts stud post to standard top post,Positive and Negative,Lead construction,Steel threaded insert