5/16"-18 Grade 8 Yellow Zinc Finish NE Steel Nylon Insert Lock Nut / THREAD CLASS: 2B THREAD DIRECTION: RIGHT-HAND NUT STYLE: A12 HEXAGON NUT HEIGHT: 0.269 INCHES NOMINAL END ITEM IDENTIFICATION: R19TM900GPMFL WIDTH ACROSS FLATS: 0.497 INCHES NOMINAL THREAD SERIES: UNC THREAD QUANTITY PER INCH: 18 NOMINAL THREAD SIZE: 0.313 INCHES PART NAME ASSIGNED BY CONTROLLING AGENCY: HEX NYLON INSERT LOCKNUT, GRADE 8, YELLOW ZINC PLATED MATERIAL: PLASTIC NYLON LOCKING INSERT MATERIAL: STEEL COMP 4140 OVERALL EXCEPT INSERT SURFACE TREATMENT: ZINC OVERALL EXCEPT INSERT SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: ASTM F1941 ASSN STD SINGLE TREATMENT RESPONSE OVERALL EXCEPT INSERT