An external permanent magnet intended for magnetic coupling with an in situ magnetic balloon catheter, positioned at the distal end of a colonoscope, to facilitate magnetic anchoring or manipulation of the catheter/colonoscope, for e.g., manual colonoscope straightening in cases of a difficult colonoscopy (also known as looping or twisting). It is intended to be placed on the abdomen in the desired position when in use and includes a portable shield with electronic indicators designed to allow safe storage of the device avoiding magnetic interference. The catheter and colonoscope are not included. This is a reusable device.