Magnetic Constant
The constant (mo/4p) is a seemingly strange way of writing a constant that serves the same purpose as G and k, but that is exactly what it does.
The value: (mo/4p) = 1 x 10-7 T*m*sec/Coul (or 1 x 10-7 T*m/Amp).
In fact, the constant k is sometimes written as:
[In both cases, the sub zero on m and e indicates the field is in vacuum.]