The extended 15-round magazine is compatible with all models of the SIG SAUER P365 micro-compact, concealed carry pistol. The magazine features a unique capacity witness hole that remains visible while the magazine is inserted in a standard P365. This allows full capacity status to be verified without removal of the magazine. The installed baseplate leaves no gap when inserted into a standard P365. The 15-Round magazine also ships with an additional baseplate that can be easily installed to all XSERIES P365 models. The overall length of the magazine is extended an additional 1″ compared to the original 10rd flush fit magazine.