The dowty washer is a metal washer with a vulcanized rubber insert for use in high pressure applications where other means of washering are unsuitable. Bonded washers are now available in self centralising form, which eliminates washer offset and makes for easier installation. Dowty washers are used for making pipe joints in hydraulic systems leak free. They are designated according to the size of the pipe thread where it is used.

When the bolted connection is tightened, the washering lip is pressed against the flat surfaces. The metal washer ensures that the components to be connected are reliably and securely held. The thickness of the washer limits the compression of the elastomer washer, eliminates any over torque of the joint, thereby ensuring a reliable washering system. The internal pressure increases the washering force by energising the washering lip.