enclosed my review of the product. A video follows a little later (at present I can not adjust at Amazon).
In the commentary but one can ever copy the link to my YouTube video and then watch this.
The spare magazine is processed exactly as that which has been the Airsoft gun Heckler & Koch G36 C AEG Electric, 6 mm, while 2.5621. And in this it fits perfectly in there. If you have 2 of these can be plugged together the magazine and quickly changed. BB's can be introduced quickly by quick charger.
So if you looking for a good replacement magazine has become here find ;-)
Greeting Micha