Applications: Filaments for bulbs( incandescent) lampand fluorescents lamp. Heaters for electron tubes. Vacuum metalizing material and high temperature structural material. Filaments for halogen lamps Vibration resistant bulb filaments for automotive lamp. Feature: W31 Standard doped tungsten with excellent non-sagging property W91 Excels in non-sagging property and a best fit for high temperature use and also excels in anti-blackening property. Developed especially for halogen lamp filaments. W71 Non-sagging and vibration resistant cobalt included doped tungsten wire.