This method has particular application to the comparative evaluation of N-values obtained from the Standard Penetration Test (SPT) of soils in an open hole as in Test Method D1586. Dynamic probing involves driving a cylindrical fixed cone into the ground using a high frequency percussive hammer. The cone is attached to a 1m section steel rod with a nominal diameter of approximately 35mm and graduation markings set at 100mm intervals. Depending upon the chosen method, the drop height can be adjusted. Blows per 100mm are recorded and after every 1m section a torque reading is recorded, a further rod is then added and the process is continued until the probe refuses to penetrate the ground or the test reaches the required depth. The test is performed according to BS EN ISO 22476-2:2005.