Usually measured in ampere meters squared, it is a measure of the strength of a magnet or current-carrying coil.  
In the Kennelly approach, this quantity is measured against the field strength, and in the Sommerfeld approach it is measured against the magnetic field.  In electrons, it is given by the equivalent current, or the charge over the angular momentum over 2 pi, multiplied by the orbital area.  Usually measured in ampere meters squared, it is a measure of the strength of a magnet or current-carrying coil.  FTP, identify this quantity that is a measure of the ratio of the maximum torque exerted on a magnet.
In the Kennelly approach, this quantity is measured against the field strength, and in the Sommerfeld approach it is measured against the magnetic field.  
magnetic moment