Note-All items, including specially designed, will be classified in this FSC. a. A bushing is cylindrical in shape, hollow, and designed primarily to be inserted into a hole to reduce the effective inside diameter of the hole, and to protect the body structure about the hole from damage resulting from stress, strain, and vibration. b. A ring is cylindrical in shape, usually flat with a center hole. Rings are multi-applicational. See specific item name for designated usage. c. A shim is a thin, sometimes tapered, piece of material used to fill in space between things. See specific item name for dimensional parameters. d. A spacer is a device for holding two members at a given distance from each other.

Includes Externally Threaded Rings; Keyed and Serrated Lock Rings; Dee Rings; Instrument Retaining Rings; Shim Sets and Assortments; Plate Spacers; Ring Spacers; Sleeve Spacers; Stepped Spacers; Spacer Sets and Assortments; Sleeve Bushings; Machine Threaded Bushings; Machine Threaded Plugs.

Excludes Sleeve Bearings (FSC 3120); Pipe Threaded Plugs (FSC 4730); Piston Rings (FSC 2520, 2805, 2810, 2815, 2825, 2990, 3040, 4310, and 4820); Retaining Rings (FSC 5325); Shim Stock (FSC 9515).