ProMag Polymer Pistol Magazine Bersa Thunder .380 ACP 30-Round Black 30RD. The follower is injection molded and the magazine spring formed from heat treated chrome silicon wire. Specifications for ProMag Polymer Bersa Thunder .380 ACP 30-Round Pistol Magazine: Manufacturer: ProMag Gun Model: Bersa Thunder 380 Caliber: .380 ACP Magazine Capacity: 30 Round Fabric/Material: Polymer Magazine Type: Drum Package Contents: ProMag Polymer Bersa Thunder .380 ACP 30-Round Pistol Magazine What firearm models does the manufacturer say ProMag Polymer Bersa Thunder .380 ACP 30-Round Pistol Magazine is compatible with? The manufacturer suggests that ProMag Polymer Bersa Thunder .380 ACP 30-Round Pistol Magazine is compatible with Bersa Thunder 380ProMag DRM-A104-30RD: Polymer Pistol Magazine Bersa Thunder .380 ACP 30-Round Black