Correct length units in Pythia interface?

Reading through the Pythia interaction interface I found this snippet:

          const double sigEla = fSigma.sigmaEl();
          const double sigProd = fSigma.sigmaTot() - sigEla;

          return std::make_tuple(sigProd * 1_mb, sigEla * 1_mb);

I know that Pythia uses femtometer as internal base unit for lengths, therefore cross-sections are in fm², which is one order of magnitude different from a mb. I have the suspicion that the 1_mb is not correct.