Different He ionized regions: He⁰⁺ (blue), He⁺ (purple), He²⁺ (yellow). The sketch is oriented in a plane parallel to the line-of-sight and the sky plane. Different regions in the wind-wind collision scenario are labeled. Region 1 represents the He⁰⁺ zone in the primary wind. Region 2 shows the hot post-shock secondary wind composed by He²⁺. Regions 3–6 correspond to the zones composed by He⁺ in the primary and secondary winds. Region 7 displays the borders of the cavity walls.