ProMag Diamondback DBX 5.7x28mm Pistol Magazine 20 Round Blued 1 Pack Polymer 20RD. Specifications for ProMag Diamondback DBX 5.7x28mm 20 Round Pistol Magazine: Manufacturer: ProMag Gun Make: FN Herstal Gun Model: FN Five-seveN Caliber: 5.7x28mm Magazine Capacity: 20 Round Fabric/Material: Polymer Package Contents: ProMag Diamondback DBX 5.7x28mm 20 Round Pistol Magazine What firearm models does the manufacturer say ProMag Diamondback DBX 5.7x28mm 20 Round Pistol Magazine is compatible with? The manufacturer says that ProMag Diamondback DBX 5.7x28mm 20 Round Pistol Magazine is compatible with FN Five-seveNProMag FNH-A1-20RD: Diamondback DBX 5.7x28mm Pistol Magazine 20 Round Blued 1 Pack Polymer