Upgrade your AR-15 with the ProMag 9mm Magazine Quick Change Adapter Block designed for seamless integration with Colt SMG type magazines when using 9mm upper receivers. Crafted in the USA from robust polymer and reinforced with steel hardware this adapter ensures durability and reliability. Its innovative design allows for quick installation without removing the bolt stop roll pin making transitions smooth and efficient. Finished in sleek black this adapter block is tailored for AR-15 and M16 platforms delivering enhanced performance and versatility for your firearm setup.