Rollermag Features RM-30 - ProMag s new Rollermag reinvents the wheel by adding them to an anti-tilt follower in a Technapolymer magazine body. Experience a smooth anti-tilt rolling feed with the revolutionary ROLLERFOLLOWER for maximum friction reduction. Magazine is built with their ANTI-FATIGUE chrome silicon springs - so you can keep them loaded and stashed for up to 6 years without worry. Rollermag Specifications Brand: Promag Magazine Caliber: .223 Rem/5.56mm Magazine Capacity: 30 Rds Package Quantity: 1