MIL-S-21558A, MILITARY SPECIFICATION: SEALS, PLAIN OR PLAIN ENCASED, OIL (28-SEP-1973)

MIL-S-21558A, MILITARY SPECIFICATION: SEALS, PLAIN OR PLAIN ENCASED, OIL (28-SEP-1973)., This specification covers oil, plain or plain encased, seals for rotating or oscillating shafts used in Naval ordnance equipment.