A rescue tool is for use with emergency extrications from a structure. A second fabrication parameter is estimated for the selected semiconductor device. The data storing portion and data read portion comprising p-channel junction field effect transistors. In each of the guide sections, a radial thickness of at least one part located in the base end part is thin, a radial thickness of the front end part is thicker than that of the base end part. A second pump generates discharging pressure in the same direction as the discharging direction from helm pump against resistive pressure generated by the rotation of helm pump due to the operation of steering wheel is installed in series in part of the fully closed hydraulic circuit, so the steering resistance of steering wheel is automatically reduced by the action of the second pump.