The wolf eliminator for viola is available as wolf eliminator brass or wolf eliminator nickel-plated.
What is a wolf eliminator?
The wolf eliminator is attached at the viola between bridge and
tailpiece. It is also named wolf tone eliminator and prevents undesired
background noises. The effect of the wolf eliminator is mostly the best
if it is positioned in the upper third of the string section. The right
position on the viola strings is found through slight moving in
direction of the bridge or away from it.