These magazines work using a tensioned mainspring (similar to a mechanically wound timepiece) or an electrically driven feeding gear. The advantage of these magazines is the simple fact that they are able to hold a great many BBs. Most beginner or intermediate AEGs come with a high capacity magazine. The distinguishing feature of Hicap magazines is the teeth of the star wheel visible on the bottom of the mag. Simply wind the wheel until a more audible clicking noise is heard and it is more difficult to spin the wheel. Speedloaders are not needed with this type of magazine, just a big bag of BBs and funnel to direct their flow.
For Tokyo Marui, Classic Army, ICS, B&T, ASG, JG, Umarex, Elite Force and compatible MP5 series Airsoft AEG.