Single Magazine Base Pad for Ruger Mk II, MkIII, and Mk IV by Majestic Arms

Single Magazine Base Pad for Ruger Mk II, Mk III and Mk IV
  Magazine Base Pads are common in action pistol shooting because they give more reliable seating of magazines under speed loading situations. But with the Ruger Mk II and Mk III pistols, these magazine base pads are especially nice due to the recessed design of the original Ruger Mk II and Mk III magazine system. And now, the new Mk IV pistol is especially suited due to the force required to seat against its internal magazine ejector.
  These new Magazine Base Pads fit both Ruger Mk II, Mk III, and Mk IV Pistol Magazines (Sorry, Not Mk I nor 22/45). Installation is as simple as disassembly of the magazine for cleaning... Just swap the Base Pad with the original factory mag base. When you're done you'll have a more functional and better looking mag!