ETBB31 Tungsten Bucking Bar #31 Tungsten bucking bars are known to be better riveting tools than the old carbon steel bars. Tungsten bars are heavier, offer better shock & vibration dampening. Tungsten bucking bars are recommended by many health and safety organizations. Cobalt-Free! 100% environmentally safe as well as ergonomically friendly. Custom designs available upon request! FREE engineering service available for qualifying orders