Ruger Comb Riser Kit Ruger American Rifle Gen 2 Black. The rifle ships with the LOW comb installed which adds 1/2in to the comb height appropriate for many shooters using mid-power magnified optics. The comb risers in this kit provide additional comb height to present the shooter's eye directly behind the sight. One comb in the kit adds 5/8in to the comb height; the other adds 3/4in to the comb height. Combs are easily changed by loosening the recoil pad assembly and sliding the comb off. A 1/8in hex wrench or similar tool is required to loosen the rear swivel stud to change combs. Specifications for Ruger Comb Riser Kit: Manufacturer: Ruger Color: Black Last Chance: Yes Package Contents: Ruger Comb Riser Kit Ruger 90746: Comb Riser Kit Ruger American Rifle Gen 2 Black