GSD offers 308nm excimer UV-light system, is gold standard for Vitiligo and Psoriasis. The light source as illumination is generated from a molecule consisting of Xe atom and Chlorin atom under the effect of electric field, which can induce T cells apoptosis and improve pigment synthesis. GSD 308nm Exicmer UV-light system has maximum energy density 6000mj/cm2 and various spotlight lampshade with maximum light spot 25.62cm2, it can reach a rapid and high effective treatment for patients.