The FN® 509C™ 9mm 17-Round Magazine is a factory OEM magazine, constructed of heat-treated stainless steel with a black finish for superior durability and corrosion resistance in any environment. The steel wire internal spring and anti-tilt polymer follower ensure flawless feeding, while numbered witness holes allow for quick, visual round counts in the field. The polymer extension sleeve integrates with your pistol’s frame for snag-free carry, while the removable floor plate allows for quick disassembly for maintenance and cleaning. Better yet, this magazine is precision-engineered for a snug, wobble-free fit for added reliability.