It’s currently raining in Northern Nevada so I just finished up with a silver sharpie using the “dot matrix” indents on these newer Gen3 pmags. I decided to mark all of my range mags with a “T” for “training” so I can use/abuse them without too much worry. I keep a couple mags in my car so I marked them “CAR1/CAR2” and the same for a couple mags I throw into my bug out bag “BOB1/BOB2.”