By plotting the eigenstates of the finite chain as function of position, one can show that there are two distinct kinds of states. For non-zero eigenenergies, the corresponding wavefunctions would be delocalized all along the chain while the zero energy eigenstates would portray localized amplitudes at the edge sites. The latter are called edge states. Even if the eigenenergies lie in the gap, the edge states are localized and correspond to an insulating phase.