Internal chemical profiles of He and H (upper panels) and the propagation diagrams (lower panels) for the ELM WD template model with M_∗ = 0.1554 M_⊙ and T_eff ≈ 7860 K (left) and the pre-WD template model with M_∗ = 0.2389 M_⊙ and a similar T_eff (right). The grey areas in the 0.2389 M_⊙ model indicate a thick inner convective zone at 0.3 ≲ r/R_∗ ≲ 0.9 and another, very thin outer convection zone, at 0.988 ≲ r/R_∗ ≤ 1. Dashed horizontal lines represent the three frequencies detected in SDSS J222859.93+362359.6.