This aftermarket Winchester 1200/1300 magazine extension for 12 gauge shotguns is a 7 Shot mag extension made from fluted Military type III hard anodized 6061 T6 aluminum. This 7 shot Mag Extension has a tactical shotgun standoff device cap. This ATI premium Winchester 7-Shot fluted magazine extension with stand off cap holds two additional 2.75-inch shotgun shells, increasing the total capacity of a 12 ga Winchester 1200/1300 to seven shells. It installs easily on compatible shotguns with barrel lengths of 18.5-inches or more. The extension's exterior diameter matches that of the shotgun's barrel lug for a seamless appearance, while the ratchet base allows for a snug, secure fit. The extension incorporates a magazine spring and extension stand-off cap. Virtually indestructible, Made in the USA. ATI Limited Lifetime Warranty.