An item generally round in shape and usually having a centrally located hole. It has at least one flat bearing surface. It is made of precious or semi-precious gem (ruby, sapphire and the like), natural or synthetic. It is intended for use in precision instruments, meters, timing devices, clocks, and the like.
used with screws 20000740, 20000687, and plate assy 400193 special features, to 5n11-2-11-33 reference data and literature, aircraft mechanical clock 6645-00-076-3050 end item identification, jewel part name assigned by controlling agency