The Ruger American Rifle Generation II Stock features a Comb Riser To Adjust The Height Of The Comb For Improved Sight Alignment. The Rifle ships With The Low Comb installed Which adds 1/2'' 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 5/8'' To The Comb Height; The Other adds 3/4'' To The Comb Height. Combs Are Easily Changed By loosening The Recoil Pad Assembly And Sliding The Comb Off. A 1/8'' Hex Wrench Or Similar Tool Is required To Loosen The Rear Swivel Stud To Change Combs.