The INVR mounts in the barrel channel of the KRG Whiskey-3, X-ray, or TRG-22/42 chassis and provides mounting options for night vision and other items. At the top is a Picatinny rail for mounting clip-on night vision devices. On either side are mount points for a QD Sling Plate, Sling Loop/QD Mount, or an L2 rail. The bore diameter is 1.15" so it will accept many heavy barrel contours. With some work it can also be made to fit in all versions of our Spigot Mount. Fits: All Whiskey-3 Chassis, all X-ray Chassis, TRG-22/42. Restrictions: Requires removal of steel insert plate on TRG's, can't use TRG bipod or very heavy barrel contours. Weight: 4oz Mfg: Kinetic Research Group