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 5920-00-957-0777
NSN 5996-01-170-1915
NSN 6135-00-756-6149
NSN 5930-01-317-3892
NSN 5975-01-606-4988
NSN 5996-00-419-9634
NSN 5985-01-165-0411
NSN 6620-01-494-8667
NSN 5920-00-373-3636
NSN 5985-01-412-0569
NSN 5930-01-469-9714
NSN 5975-01-228-5888