A thin flat metal or plastic item of various peripheral shapes having a solid or laminated cross-section. it is designed to maintain a predetermined distance between two surfaces. for round items without a hole and having a solid rectangular cross-section use disk, solid, plain. items with either (1) a solid (not laminated) cross-section, or (2) a non-separable laminated cross-section with one hole centrally located, must have a thickness less than 0.006 inch (0.152 mm) for items less than 1/4 inch (6.35 mm) outside diameter or shortest distance across peripheral flats, and less than 0.016 inch (0.406 mm) for items 1/4 inch (6.35 mm) or more outside diameter, or shortest distance across peripheral flats. for items with thickness greater than those indicated above, see spacer, plate; washer, flat and spacer, ring. when thickness and/or outside diameter or shortest distance across peripheral flats is designated as a tolerance dimension, the maximum dimension will be used to determine compliance. see also shim stock, laminated; shim stock assortment, gasket; and bearing, washer, thrust.