PHROBIS not only on the M9 bayo. Link :
 

Yes, that's correct. Mickey Finn designed and manufactured a small number of slides for the Beretta M9 pistol. The Navy SEALs were experiencing a problem with the slides failing and blowing off the frame after several thousand rounds. You can read about it at the link provided above. Beretta fixed the problem (without acknowledging there was a problem) so the Navy did not need the redesigned Phrobis slide. There were only about 26-28 of them made. They are extremely scarce today and both Phrobis and Beretta collectors would love to have one.