This will FIT ALL P320 FCU's to include 9mm, 40, 357, and 45. This will also work on the new Gold Custom works FCU. 

1. Choose a slide in either Black (Nitron) or Stainless Brushed Finish (white)

2. Choose a Caliber either 40 S&W or 357 Sig or Both

If you have any questions please let me know.