Automatic Electric Guns (AEGs) are BB guns that use battery and motor as power source. Among all manufacturers, Marui is the most popular and reliable one. From law enforcement SMGs like the MP5, to military rifles like the M4A1, Marui has done a good job on the replicas either on the appearance or the ease of maintenance. Another manufacturer, "TOP", specializes in light machine guns like the FN M249 Minimi & M60 Series.