Electro-fusion fittings have complete specifications and breeds, which also confirm to China National Standards and International Standards. The highly qualified materials of electro-fusion fittings apply to high density PE and medium density PE. Welding voltage is 39.5 V, which is consistent to the international security voltage. Bar code supports all the welding machines that can read the codes, as well as provides the best jointing parameter. The special observation hole designed by patent techniques can realize the automatically regulating weldinh. The roomy welding area and entrance area eliminate bending stress, therefore guaranteeing credible and safer interface.