Evolution models of TOI-1130 b and TOI-1130 c, compared to Neptune and Jupiter, respectively. All models assume a central ice-rock core overlain by a solar composition hydrogen-helium envelope. The M_core value corresponds to the mass of the core while M_env corresponds to the mass of the envelope. The range of envelope mass compatible with the observational constraints is shown for TOI-1130 b and compared to a similarly simple model of Neptune. For TOI-1130 c, only an upper limit on the core mass can be derived. For all cases, additional uncertainties on the core and envelope masses arise due to the unknown interior composition, temperature structure, and equation of state uncertainties. The black error bars correspond to observational constraints on the age and the radius of TOI-1130 b and TOI-1130 c.