W71 Non-sagging and vibration resistant cobalt included doped tungsten wire. Applications: Vibration resistant bulb filaments for automotive lamp. Chemical Composition(%): W :above 99.95 Fe: below 0.01 Mo: below0.01 K: 75 to 90ppm other impurity, each below 0.02 All specifications for the items are according to the standard of Jiangxi Toshiba Metal Materials Co,.Ltd