https://everyspec.com/MS-Specs/MS9/MS9300-9399/MS9359B_9552/
MS9359B NUT CASTELLATED HEXAGON A-286 SILVER PLATED
Title: MS9359, Version: B, Date: 1986-Jun-18, Desc: NUT CASTELLATED HEXAGON A-286 SILVER PLATED (18 JUN 1986) [S/S BY SAE-AS9359]
nutcastellatedhexagonsilverplated