This 13-round magazine from ProMag is compatible with Glock G21 and Glock G30 45 ACP pistols.The magazine body is constructed of a proprietary DuPont Zytel-based polymer with a full-length steel internal insert stamped and welded just like the factory magazine.In addition it has a spring made from heat-treated chrome silicon wire and an injection-molded magazine follower for consistent and reliable feeding.ProMag Glock G21/G30 Magazine45 ACP Caliber13 Round CapacityCompatible With:Glock G21 modelsGlock G30 modelsOrder your ProMag Glock G21/G30 magazine online today!Shopping for ammunition? Score big savings and fast shipping when you shop our large selection of cheap bulk ammo for sale.Score big savings and fast shipping on all our best-selling ProMag rifle and pistol Magazines available online at Ammunition Depot.