Advantage Arms Pistol Magazine, 22LR, 10 Rounds, Fits Glock 20, 21, Polymer, Matte Finish, Black AACLE2021 Advantage Arms is excited to offer their high quality .22 Long Rifle conversion kit magazine for Glock G20 and G21 firearms. This magazine is made from a durable polymer" features a 10 round capacity" and is designed to be used in conjunction with an Advantage Arms Glock 20/21 rimfire conversion kit. It also features a last round hold open. This is the perfect option for shooters who want to train at the range with their carry/duty pistols" but also want to save money on ammunition. It requires an Advantage Arms Conversion Slide Kit (not included).