This unit replaces the magazine base plate on the SIG P365 (12 round magazines). This extension does not alter the capacity of the magazine. It adds approximately 1/4" inch additional gripping surface and acts to enhance the overall ergonomics of the grip. The addition of this product serves to keep the shooters grip firm and consistently in place while using the longer 12 round magazines.

**Not for 365XL magazines(10 or 12 round).