Odin Works Pistol Magazine Base, +5 Rounds, Anodized Finish, Fits Sig 320 9mm, Black ACC-PMB-SS-320-BLK Guaranteed to give you an edge" ODIN Works has designed their PMBs (Pistol Magazine Bases) with the competitive and noncompetitive shooter in mind. Introducing the SIG Sauer 320 PMB: Ergonomically machined to fit perfectly in the palm of your hand for effortless stripping" the weighted base allows for rapid mag changes and 5 extra rounds all while remaining well within the 140 mm gauge limits of USPSA.