NOTICE!
MAY HAVE SOME SCRATCHES OR MICRO DENTS HERE AND THERE. 8.5~9/10 EXTERIOR CONDITION! I HAVE SIX OF THESE, 2017 ERA.
FAULTY or SEMI faulty A&K M249 box mag with various issues. You may need to take it apart and reassemble it. Re-solder the wires, replace/reoil the BB feeding ramp, replace a switch or two, etc etc.
There are extensive guides on YT on how to service this. So buy it on a discount and do it on my behalf so these can stop collecting dust on our "need to repair bin".
A&K M249 2500 rounds electric box magazine