What it is
AN960 flat washer, Flat washer, fits 5/16 bolt or screw; ID (A) .328" ±.010; OD (D) .562", thickness not decoded: Table I prints T = .016 / .032 / .063 for this size; the aluminum and brass columns are not row-aligned with T on the scan
Equivalents
No equivalent on file: no maker document names one and the government catalog lists none on its stock number.
Install tooling, by who made the part
Not documented for this part number. Ask a tooling specialist →

Reference only: the drawing and its process spec govern. How to read this

Full detail: decode, cited documents, every stock number
AN960D516L | SpecLok