From MAG, this magazine for the AEG M249 holds 2500 rds which are wound via motor powered by a 9v battery (not included) operated by tethered switch.
The compact size of this magazine makes it easier to worth with the otherwise encumbering giant mass that comes with the M249 initially. This mag also comes with a handsome nylon cover in DPCU camouflage pattern for a hardwearing cover that also looks good and simulates the bag style magazine used by armed forces around the world.
Included are two different feed plugs, one feeds the CA M249 whilst the other feeds the TOP M249; the default mounted one is for the CA, simply switch to the other if needed; the instructions included explain what you need to do.
The switch is on a wire which can be spooled internally by simply tucking it in; adjust the amount of wire you need to mount your switch as needed then simply tuck back in the excess to keep things neat and free to reduce snagging on the surroundings. Included in this set is a pair of small sticky back Velcro pads which you can use to attach to the switch and your intended mounting surface as needed to affix your switch conveniently.