The distribution of the secondary masses Φ(M₂) (normalised such that ) extracted from the inversion of the mass functions f(M₁,M₂), assuming a random orientation of the orbital planes on the sky and a fixed primary mass M₁ = 0.8 M_⊙ (top) or M₁ = 0.9 M_⊙ (bottom). For comparison, we also show, with a dashed red line, a Gaussian distribution of masses centred around M₂ = 0.56 M_⊙ (top) or M₁ = 0.6 M_⊙ (bottom), with a standard deviation of 0.075 M_⊙ in each case.