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 6110-01-326-1013
NSN 5910-01-560-5681
NSN 6685-00-100-4753
NSN 6145-01-633-3558
NSN 5975-01-523-0425
NSN 6610-01-437-0961
NSN 5960-00-161-9345
NSN 5910-01-110-1140
NSN 2925-01-575-3192
NSN 5999-01-358-4702
NSN 6150-01-415-8035
NSN 2925-01-079-6229