1/2"-20 Grade 18-8 NTE Stainless Steel Jam Nylon Insert Lock Nut / THREAD CLASS: 2B LOCKING FEATURE: PREVAILING TORQUE WITH NONMETALLIC INSERT NUT STYLE: A12 HEXAGON NUT HEIGHT: 0.298 INCHES MINIMUM AND 0.328 INCHES MAXIMUM WIDTH ACROSS FLATS: 0.741 INCHES MINIMUM AND 0.752 INCHES MAXIMUM THREAD SERIES: UNF THREAD QUANTITY PER INCH: 20 NOMINAL THREAD SIZE: 0.500 INCHES MATERIAL: STEEL CORROSION RESISTING OVERALL