A washer having a centrally located hole with a solid or laminated cross-section and two flat parallel bearing surfaces. The hole must be 75 percent or less than the largest dimension and the bearing surface finish is greater than 32 microinch (0.8 micrometer). The thickness cannot exceed 25 percent of the largest outside dimension. When the largest outside dimension is less than 1/4 inch or 6mm, the thickness must be 0.006 inches (0.15mm) or greater and for items 1/4 inch (6mm) or larger, the thickness must be 0.016 inches (0.4mm) or greater. The maximum tolerance is applied to dimensions and used as a determining factor. Items with separable lamination use shim. For items fabricated from ceramic or electrically rated materials by specification or industry standards use insulator (1), washer. Excludes disk, valve, graphite impregnated and lubricated items.
Dept. of the Navy 
Turkey Classification: Gaskets, washers and other seals, of vulcanized rubber other than hard rubber
NSN 6620-01-462-1625
NSN 6145-01-498-1987
NSN 5999-01-169-8202
NSN 6645-00-229-1521
NSN 5910-00-373-8808
NSN 5925-01-137-6161
NSN 6135-01-426-8282
NSN 5910-01-483-0621
NSN 6685-01-498-9983
NSN 5999-01-496-8630
NSN 5996-01-071-4828
NSN 5950-01-566-5449