Also known as 9mm ULTRA and 9mm POLICE. Was origially built for the German police, and not avaiable to civilians untill 1975. Was develpoed to be slightly more powerful than a .380 and be used in pistols such as the PP, SIG 230 and I think B76. Iguess at the time the full size 9mm pistols were considered to heavy and bulky so this was there alternative.
Ammo can be found in a couple places but is very expensive