Add three rounds of capacity to your Magpul AICS magazine with the MK Machining Pro Series Magpul AICS extensions. Redesigned shape for increased strength and durability. Now printed from our tough PA12 Nylon Material. Easily installs in under a minute, simply remove baseplate and slide on extension, then reinstall baseplate. Proudly printed on top notch machines from our custom PA12 Nylon. Extremely lightweight, lifetime warranty, and made in the USA! Reuses stock spring and follower.