Our take: This metal shell JG 300 round M4/ M16 high capacity magazine fits and feeds in a wide variety of metal gearbox AEGs that use M4/ M16 style magazines. This high capacity airsoft AEG magazine uses a gear wind-up system similar to other AEG magazines on the market.
Construction: Metal Shell/ Polymer Internals
Capacity: 300 rounds 6mm airsoft BBs
Compatibility: Fits most M4/ M16 metal gearbox AEGs including JG, CYMA, DBoys, Echo1, A&K, CA, TM, G&P and VFC
Package includes: 1x 300rd M4/ M16 High Capacity Magazine