|
That looks like one of these made by CAA that someone cut in half: http://www.brownells.com/.aspx/pid=17844/Product/AR_15_M16_MINI_14_AK47_reg__MAG_COUPLER
I have a couple of them, and they're ok, but not too durable. One on a pair of Pmags broke, but it's still useable because the upper half is still working. The Arredondo seems more robust, but I've heard of them breaking and they take some work to get onto a Pmag. Probably the best one right now is the Firebird. It's made for Pmags, is easy to install, and nearly indestructable. Brownell's has them, too: http://www.brownells.com/.aspx/pid=27286/Product/AR_15_M16_FIREBIRD_PMAG_COUPLER |
