Sig Sauer CALXMPX4B9G2 Caliber Exchange Kit 9mm Luger Sig MPX Gen II Black Carbon Steel
https://www.tandktactical.com/shop/798681555062-sig-sauer-calxmpx4b9g2-caliber-exchange-kit-9mm-luger-sig-mpx-gen-ii-black-carbon-steel-30533
https://www.tandktactical.com/web/image/product.template/30533/image_1920?unique=f2a4dcb
This is a 4.5" barrel for the Second Generation of the MPX Platform.
