It has been widely used in ports, steel plants, power stations, ships and garbage treatment plants, and is used together with tower cranes, ship cranes, ship unloaders, traveling cranes and other type of cranes. It has a Electro-Hydraulic system that works with electricity. Its motor force is inceased related to diving force into the bulk material. It is used by a control panel. The mechanical structure for opening & closing is succinct and inventive. No maintenance required except greasing. It is easy to use and can work under any circumstances in order. NOTE:please show these informaions in your inquire : one : how much is your crane total lifting capacity ? which material the grab will unload ? or two :if you have ensure the grab volume,then tell me which material the grab will unload ? we can provide a perfect proposal for you with the informations you give to us .