The Gilbarco def pump hose is a flexible, durable coolant hose designed specifically for use in automatic lubrication systems and hydraulic applications. Its special blue color helps to identify it as a DEF hose.the gilbarco def hose is a flexible, durable coolant hose designed specifically for use in automatic lubrication systems and hydraulic applications https://empirelubeequipment.com/collections/def-diesel-exhaust-fluid-equipment-1