Incredible product!! I had 3 Tokyo Marui 1911 mags, 10+ years old, which all badly leaked gas. I filled each mag up with this product. Initially they still leaked, so I filled again and a third time, during which the leaking gradually decreased on 2 of the Mags until gas tight. The other mag took a few more fills but is now leak free holding gas. I used about half a can to fix 3 mags.