ETS has been making its AR15 couplers since at least 2015 as far as well can tell and, for about $20 a pop, they have a lot of neat features. Besides having a translucent body – allowing for a quick ammo count and type check – they have a built-in coupler on each side of the magazine body that allows multiple mags to be connected in seconds with no tools or extra parts. In short, a "jungle mag" without tape, clips, or bands.
The concept isn't new, as HK and SIG (as in Swiss SIG, not American Sig) produced coupler mags for their collective 5.56 platforms, but the ETS type is American-made and comparable in cost to a Magpul PMAG, so there's that. They can be run separately or – within a second – attached to each other to run as a coupled mag setup.
The design is instinctive and easy to figure out.
The mags, even with the side couplers, are not snag-traps, and we found they can be used with normal AR-style single magazine pouches when separated. However, the extra girth of the coupler attachments means we couldn't find a double mag pouch that would accept two of the ETS mags, even when uncoupled.
ETS says its mags won’t crack or break when dropped – which we verified with several lobs to the concrete on the range – are resistant to harsh cleaning chemicals, and won’t become brittle over time even when exposed to harsh environments or extreme cold.
The weight difference between the 30-round ETS Coupler and the same capacity PMAG is negligible, with the two unloaded mags hitting the scales at 5.1 and 4.8 ounces, respectively.
When it comes to functionality, we tried our pair of ETS test mags in several different AR platforms as well as the new Springfield Armory Hellion bullpup and had no failures to report over the course of about 500 rounds of mixed .223 and 5.56.
Two mags, coupled together and filled with a total of 60 rounds of M193 ball, with the tops attached, weigh in at 36.6 ounces, or slightly over two pounds.
ETS says its mags are creep resistant and that the feed lips and body won't spread when being stored long term, even when fully loaded. We've got our two test mags filled to the top with 62-grain M855 green tip and will revisit that claim in a couple of months.
In the end, the ETS AR15 coupler mags work as advertised, are easy to clean, attach/detach, and are inexpensive. While they don't have the same panache of a PMAG and aren't as cheap as some aluminum-bodied mags, they shouldn't be ruled out. Additionally, the fact that they allow the user to instantly verify ammo status makes them great for range trips and training sessions.