The authors present results from an inversion procedure that derive the temperature stratification, the turbulent velocity, and the magnetic field strength of the photospheric layers of magnetic fluxtubes from observed Stokes V spectra near disk center. In a first step the inversion has been applied to 10 Fe I and Fe II Stokes V profiles of a plage and a network region to obtain reliable models of the fluxtubes. In a second step the dependence of the fluxtube structure on the filling factor has been studied with spectra of 3 Fe I lines from 23 different regions based on the models derived in the first step.