Sig Sauer Magazine, 357 Sig, 40 S&W, 18 Rounds, Fits P250/P320 Full Size, Steel, Black MAG-MOD-F-43-18 Trusted by military" police and civilians for decades" SIG SAUER has earned a worldwide reputation for the unquestioned accuracy and unflinching reliability of its pistols and rifles. SIG SAUER magazines provide exceptional fit and reliable feeding in their high quality firearms.