  We consider a wide range of parametric mass models for B 1933+503, a
ten-image radio lens, and identify shared properties of the models with the
best fits. The approximate rotation curves varies by less than 8.5% from the
average value between the innermost and the outermost image (1.5h^{-1} kpc to
4.1h^{-1} kpc) for models within 1 \sigma of the best fit, and the radial
dependence of the shear strength and angle also have common behavior for the
best models. The time delay between images 1 and 6, the longest delay between
the radio cores, is \Delta t = (10.6^{+2.4}_{-1.1})h^{-1} days (\Omega_0=0.3,
\lambda_0=0.7) including all the modeling uncertainties. Deeper infrared
observations, to more precisely register the lens galaxy with the radio images
and to measure the properties of the Einstein ring image of the radio source's
host galaxy, would significantly improve the model constraints and further
reduce the uncertainties in the mass distribution and time delay.
