So the ions along with the pair of electrons to form that Fad H two. Now, Succinate dehydrogenate, the enzyme that catalyzes step six, is balance of the inner mitochondrial membrane. And it is an iron sulfur protein. That means it contains these iron sulfur groups that can basically abstract those electrons. Now, the Fad is actually covalently bound to that particular enzyme. And when the Fad gains those two H atoms, it becomes the Fad two and it continues to be attached onto the enzyme.