The mpx psb is an innovative, three-position adjustable pistol stabilizing brace dimensioned to fit the receiver cuts of sig mpx and mcx.It ships as a complete assembly, ready-to-install, along with an integral m1913 adjustable housing.Included is an adjustable nylon strap.Rails: BlackType: BraceFirearm Type: MPX PSBFirearm Model: Sig MCX/MPXMaterial: Elasto-PolymerFinish: Elasto-PolymerPositions: 3