Traumatic pistols are a class of less-lethal guns typically they fire rubber balls.
The pistol is named the Osa or Wasp nodding to the fact that while it won’t kill you, it’s very unpleasant to be stung by one… The pistol was produced in limited numbers between 1997 and 1999 and was a break-action, four-shot non-lethal handgun. This early version featured a shorter 45mm traumatic cartridge and a less streamlined look.
The modern version of the PB-4SP carries with it an updated look as well as a much larger 18x60mm traumatic cartridge with a rubber bullet (traumatic), signal, stun, illuminating, marking, and lachrymatory (tear gas) rounds available for use without any parts changes.
Looks like it would be useful in a wildlife deterrent context. Bear bangers and emergency flares.