That is the 12mm protruding mag release. It can easily be changed out to the 18mm flush mag release. Unfortunately it will also require changing out the grip panels which means you will loose the engraved “PSP” grips which is a huge selling point on that piece. That is more of collectors item then a range gun.personal opinion: the mag release sucks
133 digits lowers and that would be worth 3-6 times more.Nice low serial number
133 digits lowers and that would be worth 3-6 times more.