This is a solicitation for multiple related items, with awards potentially made at the individual line-item level to multiple vendors. The material is designated as SPECIAL EMPHASIS (Level I) for use in a crucial shipboard system, requiring strict quality, traceability, and certification controls. The required item is a Heavy Hex Nut conforming to ASTM-A194, with final delivery of material due 365 days after the effective date of the resulting contract. Performance of services will be subject to Government Quality Assurance at the contractor's place of performance, which cannot be changed without authorization. The contract will be a "DO" rated order certified for national defense use under the Defense Priorities and Allocations System.