50-Round 22 long rifle magazine fits Atchission/Ciener drop in conversion kits and dedicated AR-15 uppers. Also fits the Kel-Tec PLR-22 and Sig 552. The drum features a modular design with an interchangeable feed tower, allowing it to be configured to function in most AR-15 rimfire conversions, the S&W M&P 15-22, or the Ruger 10/22 by installing the appropriate feed tower (AR-15 Rimfire Upper/Conversion Tower Included, Others Sold Separately). Polycarbonate PC construction withstands heat and wear for durability and long service life. Additional Feed Towers for magazine compatibility with S&W M&P15-22 and Ruger 10/22 firearms are NOT Included and must be purchased separately.Notes:Compatible with the Following AR-15 Rimfire Conversions or Dedicated Firearms:AtchissonCienerCMMGModel 1 SalesSpike's TacticalTactical SolutionsTarget MasterKel-Tec PLR-22Sig 522