I've been beating up on some ETS mags and they are holding up well, better than most. I did at least 7 drop tests of loaded mags onto cement from about 8 feet and the mag tube held up incredibly well. No cracks to spine or feed lips where they usually fail. However, the follower inside cracked. Throwing them into a fence did nothing, so I moved on to empty mag vs SUV. After replacing the follower, the mag fed fine, but did not drop free.