Each Great Company has a single Belt of Russ. The belts were crafted by master Iron Priest Stef Blacksoul following Russ' disappearance, and are said to have been based on the mighty belt that Russ himself wore. Each belt incorporates a device that generates a protective field which will protect its wearer from harm. In game terms they have the same effect as an Iron Halo (see Codex: Space Marines).
Belt of Russ
Source: Codex: Space Wolves, p. 15