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 
Italy 
Turkey Classification: Gaskets, washers and other seals, of vulcanized rubber other than hard rubber
NSN 5990-01-054-4255
NSN 5998-01-357-6348
NSN 6685-00-987-0736
NSN 5999-01-353-5601
NSN 5855-01-406-4821
NSN 5990-00-067-1622
NSN 4140-01-058-5123
NSN 6610-00-982-6768
NSN 6105-01-252-8847
NSN 4140-01-296-3365
NSN 5910-00-404-7860
NSN 5965-00-378-3403