CMC Products RPM or Railed Power Mags are some of the STRONGEST 1911 MAGAZINES made. The RPM design is the result of a relentless pursuit of excellence, maximizing reliability and durability under all conditions. The dual wall feed rails have revolutionized 1911 magazines. No more jams due to thin, warped and bent feed lips! The feed rails built into the RPM are at least twice as strong as any traditional 1911 magazine feed lips and provide the smoothest feeding surface..45 ACP CaliberFits All Full-Size (Government Model) 1911 Handguns8 Round CapacityAt Least 2X the Service Life over other 1911 MagsFeed Rails Provide Smoothest Feeding SurfaceHeavy-Duty Corrosion Resistant Stainless Steel BodyLaser Welded TubeNumbered Witness Holes for Visual Round CountPatented RPM Follower is Alloy Frame Safe18 Coils of High Tensile Rocket Wire SpringRemovable Base Pad for Easy CleaningSmooth Finish for Easy Insertion / RemovalLong-Lasting Function in Dirty EnvironmentsCMC's 100 percent Satisfaction Guarantee