Pole 6 : The area on a magnetized part from which the magnetic field is leaving or returning into the pipe, i.e., substantially perpendicular to the pipe surface. (RP 5A5)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}