For performance plumbing connections that require a crushwasher, trying to re-use an old washer is not recommended. A crushwasher creates a seal specific to its application by deforming (crushing) as the connection is tightened. A new high quality crushwasher, like these Aeroquip crushwashers, can give you an excellent seal, but a used crushwasher has already been compressed, so it may not adequately conform to the new connection. This package contains 5 replacement aluminum crushwashers that are size -04. Please note: Eaton Aeroquip fitting tolerances are engineered to match Eaton Aeroquip hose tolerances. The use of Aeroquip fittings on hose supplied by other manufacturers and/or the use of Eaton Aeroquip hose with fittings supplied by other manufacturers may result in the production of unreliable and unsafe hose assemblies and is neither recommended or authorized by Eaton.