The Ruger American Rifle Generation II stock features a comb riser to adjust the height of the comb for better sight alignment. The rifle comes with the LOW comb installed, which raises the comb height by 1/2&';&';, suitable for many shooters using mid-power magnified optics. The comb risers in this kit provide extra height to position the shooter&';s eye directly behind the sight. One comb in the kit increases the height by 5/8&';&';, while the other adds 3/4&';&';. Combs are easily swapped by loosening the recoil pad assembly and sliding the comb off. A 1/8&';&'; hex wrench or similar tool is needed to loosen the rear swivel stud for changing the combs.Features : Includes 3 Combs "Sizes: 1/2", 5/8", and 3/4"" Compatible with : Ruger American Rifle Gen II