Disclosed herein is a welding helmet in which a worker may transmit and block external light as necessary by forming a light switching window for blocking external light from a side surface of the welding helmet. The roller type hyperthermo-radiative apparatus includes a backing plate with wheels fixedly supported at four corners thereof. An important partial structural feature of the compounds which provides the non-teratogenic effect and lack of irritation of skin is shown by the formula where the partially drawn ring signifies an aromatic ring which may be carbocyclic or heteroaromatic, 6-membered or 5-membered, and may be condensed with another ring.