Advantage Arms .22 Caliber Conversion Kit - For GLOCK 20/21 GEN4

In ten short seconds, you can have your Glock 20, Glock 21 or Glock 21SF GEN 4 ready to shoot inexpensive .22LR ammunition. Features a patent pending system that locks the slide open after the last round is fired. Comes with slide assembly, recoil spring assembly, barrel, one magazine, magazine loader, cleaning patches, brush, cleaning rod, cleaner lubricant and carry case.