This factory replacement, optic ready, P320 X-series Stainless Steel slide assembly fits Carry and Compact size (X-series & non x-series) grip modules. It accommodates the 3.9" barrel. This slide is cut for the Romeo1Pro covered by a removeable sight plate and is equipped with standard height, X-ray night sights. It will also accommodate optics with the Deltapoint pro footprint. *Note, only for use on 9mm/ .357SIG / .40S&W firing control units (FCU). It will not function with a .45 ACP FCU.