The ProMag® .40 S&W 15-Round Magazine for Glock® 22 pistols features a durable, steel-lined DuPont™ Zytel® polymer body with numbered witness holes for visual round counts, while precise tolerances ensure a snug, reliable fit. Plus, a heat-treated chrome silicon wire internal spring and an injection-molded polymer follower work together to deliver flawless operation. Made in USA.