Mass distribution obtained from the four SPH Aquarius haloes, compared with four different halo contraction implementations at z = 0, 1, 2, 3, and 4 (from top to bottom for each halo). The AC models are Blumenthal et al. (1986; blue lines), Gnedin et al. (2004; pink lines). We also compare with the empirical models from Abadi et al. (2010; orange lines) and Pedrosa et al. (2010; green lines). The vertical grey line indicates the 5% virial radius at each redshift. We include the residuals between the mass distribution of the SPH haloes with each AC model.