SHOOT WITH THE BEST This is a factory extended magazine for the SIG Sauer P250 or P320. It will fit and work in any P250 or P320 chambered in 9mm but there will be a gap between the grip shell and the magazine extension on the Sub Compact and Compact. It will fit properly with the magazine extension meeting the grip frame with the Carry and Full Size. This magazine holds 21 rounds so you can shoot longer between reloads.