Electric arc tube for high pressure sodium lamp (HPS lamp) Electric arc tubes are made from our high quality PCA tube with electrodes of columbium tube or columbium wire by special equipment. They are the main components in HPS lamp. The arc tube has a high pressure inside for higher efficiency. Sodium, mercury and xenon are usually used inside the arc tube. The arc tube is made of aluminum oxide ceramic which is resistant to the corrosive effects of alkalis like sodium. We can supply European standard and American standard and the other special types according to the requirement. European standard: NG35W-NG1000W American standard: LU35W-LU1000W