MXT EXTENSION TUBE KIT, 12GAThe Nordic Components MXT 12GA Shotgun Magazine Extension Tube increases the existing shotgun capacity and from 6061 aluminum that is anodized. Used in conjunction with the MXT extension tube nut, this tube kit will add the stated number of rounds (+1 to +9) to your existing magazine capacity. All capacities are measured using 2. 75 star crimped shells; for use with 3 or 3. 5, increase your selection by one or two rounds. Features: Anodized 6061