This simple and discreet mag carrier can be worn IWB or OWB, with rounds forward or rear, making it a versatile companion for everyday carry. Comes standard with a top-of-the-line DCC Monoblock belt clip. The mag should be inserted with the rounds facing toward the folded edge of the carrier, not toward the retention screw. If you intend to carry your spare mag AIWB, Henry Holsters recommends an extended length carrier. Fit Guide: S1/Steel1 - will fit many different double stack steel mags: CZ P10/P07/P09 Sig P320 FN509 M&P 9mm/.40 Springfield Echelon HK VP9 Beretta PX4/PX4C It will NOT work for slim steel mags like the Walther PDP, Sig P226 or Beretta 92/M9.