Self-locking jack is mainly used for supporting heavy loads for long periods where it can still support the removal of heavy oil, and safe and reliable. Can be used underwater, single-acting, load retraction, self-locking nut so that the load safer, especially for major projects, is easy to operate controls and hydraulic jacks, designed with safety packing unit, built-in pressure relief valve to prevent overload to protect jack in order to facilitate safe operation. The device is connected, using a high-pressure hose and threaded connector, with the use, fast, and quick to overcome shortcomings of traditional joint oil is mainly used for electric power, construction, machinery manufacturing, mining, railway bridges, shipbuilding and other industries equipment installation Remove from the top job. More about self-locking jack, hydraulic jack products, please visit http://www.jstzhl.com inspection.