This is an older crystal mouthpiece, branded "Selmer Italy" and almost certainly made for the Selmer company by someone like Pomarico.
It has a medium-large bore - almost as large as a Boosey and Hawkes 926/593 and larger than a typical Vandoren mouthpiece.
I personally found the lay a bit too close for me.
The tip is good and the rails, while a bit thick, are in good condition and the table looks fine.
There is a small chip (clearly visible in the pics) in the bottom edge of the "window", where it looks as if someone (before I got it) has been over-enthusiastic with a cleaning swab (perhaps one of the old-style mops with a wire core) and knocked a chip out of the throat.