It is a tool used to destructively remove an over tightened and/or corroded nut from a stud or bolt - ideally without damaging the thread.
Hydraulic nut splitters attach to a hydraulic pump to break apart corroded or frozen nuts to free the bolt.
he nut splitter is placed around the nut and a blade is pushed through the nut to cut it free from the bolt. Industrial nut splitter tools are used to break nuts in a variety of applications, including off pipe flanges, machinery, and structures.
A hydraulic nut splitter uses a hydraulic cylinder in place of a threaded shaft that must be turned manually. More expensive models use pneumatics or hydraulics to make the process faster and easier.