People often equate the two, but thickness is a physical measurement while puncture resistance is a performance rating, and they mean different things. A 1/4" thick piece of felt can easily be punctured with a screwdriver, but a thin piece of ripstop fabric won't budge.
RPE has a powerful internal woven grid that resists punctures and tears, just like ripstop fabric. In fact, it takes 3 times more force to puncture RPE than an unreinforced rubber sheet that's twice as thick.



