These products are mainly used for opening the Cylinder Head for main engine maintenance, loosening very tight bolt & nut. During the maintenance work, hose assemblies may fail abruptly and unexpectedly due to a variety of reasons. Hydraulic oil shooting out at high pressure and/or at high speed can cause serious personal injury and severe damage to objects as well as pollution of the environment. Example of potential hazards: 1. Bursting hose components. 2. Whipping hose ends. 3. Oil spray leakage. 4. Coupling blow off. Make sure for your safety that: 1. The design and operation of tools and machines complies with the existing safety regulations. 2. Inspect hose assemblies for damage and wear at regular Intervals. The inspection of hose kit should be done under zero pressure. 3. Defective or damage hose assemblies must be replaced immediately. 4. A coupling and a nipple should be connected properly and do not connect with other brand even it is interchangeable. 5. When the leakage is confirmed from the high pressure components, stop using and replace immediately. When ordering these products, please specify the manufacturer & model of Main Engine, as the original couplings are required for Main Engine. Made of steel, black zinc plating with durable design adapters, suitable for most couplings and hoses.