The Advantage Arms .22 LR Conversion Kit Magazine is designed for Glock G20 and G21 firearms, offering a 10-round capacity for efficient training and practice. Made from durable polymer, this magazine features a last round hold open, making it ideal for budget-conscious shooters looking to practice with their carry or duty pistols. To use this magazine, an Advantage Arms Conversion Slide Kit is required (sold separately). Enhance your shooting experience with this reliable and cost-effective magazine, perfect for any outdoor enthusiast.