Finished Hex Jam Nut, National Coarse (Bulk Carton)
A six-sided internally threaded fastener which is only 2/3 the thickness of a full form nut. Jam nuts are tightened against the work surface and a finished or heavy hex nut is tightened against the jam nut to keep it from loosening. * PL - Plain; ZB - Zinc Blue; HDG - Hot Dip Galvanized