With this adaptor, you can use Burris Zee Rings on your RugerA(R) rifle or handgun. It properly anchors and aligns your scope so you can consistently put rounds on the target. 2-piece, solid steel design Strong and lightweight Compatible with RugerA(R) firearms that feature the proprietary RugerA(R) integral mounting system Mfg: Burris SPECS: Steel, polished blue finish. M77A(R) fits M77 rifles, Super RedhawkA(R). Set of two bases, 1.375" (35.9mm) long and 1.980" (50.3mm) long. 77/22A(R) fits RedhawkA(R) Hunter, BlackhawkA(R) Hunter, 77/22A(R), 77/44A(R), 77/50A(R), Model 96(TM) (.44 Mag), 10/22A(R) Mag, M