I have a couple and they work as advertised. They may have issues with tight pouches.
I mentioned it in my earlier post. They offered extended mags that use a single body. Once Glock released the 24rd mag for 9mm I stopped buying the ETS version. But ETS has them for the 43, 43x, 21, and 20 (in my case G40). They also have a 40rd stick that has worked marvelously in an APC9 PRO.