1) WL10, WL15, WL20 lanthanum tungsten electrode can be able to bear high current and have the lowest burn-lost rate, it is a popular tungsten electrodes in the circle of welding.2) color mark: WL10(black)Wl15(gold) wl20 (blue)3) other impurity: <0.20% 4) diameter: 1.0 - 12.0mm 5) length: 50.00, 75.00, 150.00, 175.00mm 6) quality of surface: Ground finish, polish finish