This new Advantage Arms Conversion Kit allows your Glock 20, 20SF, 21, or 21SF to fire the .22lr round. The slide has a black finish with a 4.5" barrel. This kit comes with one 10 round magazine, cleaning kit, lube, and magazine loader. This is a complete conversion kit. Convert your own Glock to shoot .22lr rounds with this kit. This will not work on Gen 4.