Mag works great, but it should be noted that the sound activation doesn't always work. If your gearbox is quieter, you run a polarstar, or your mag isn't right up next to your gearbox (e.g. p90 box mag users), then you'll probably have to use on/off to wind this mag.
Otherwise though, no problems, and the extra rounds are great.
-Auto-winding is great compared to having to re-wind if the spring unreels
-1000 Rounds in a more realistic container (as opposed to the fat high caps with normal mag tops and wider bottoms)
-Fake bullets are a nice touch.
-Fake bullets can make it easier to mistake your airsoft gun for real steel, so be extra careful and keep it stowed if not on the field.
-Microphone may not trigger winding depending on usage (read above)
Rating: [4 of 5 Stars!]