WHAT DOES RUGER P89 FOR SALE MEAN?

For sale is a Federal Arms Company of The us 9mm threaded P89 barrel. I bought this a couple of years ago and installed it but I don't Feel I ever set only one spherical by it.I just paid $three hundred for any blue P85 in holster worn problem and sense it had been a fair offer, at the same time as a Ruger junkie I have a tough time observing P ser