'Daniel Defense' 4 inch Rail Kit (RIS Unit / Outer & Inner Barrel) (Black).

The kit includes: pistol length (4 inch) Rail, outer barrel (7 inch), tight bore barrel (53mm)

The innovative Daniel Defense Lite Rail 4.0 kit gives the weapon system an uninterrupted upper rail platform and also allows the Armorer to install the rail system with simplified alignment to the upper receiver. This kit is the lightest rail system available, and it also provide features that no other rail system possesses.