30-Round Real-Cap & 135-Round Mid-Cap mode is switchable. One button easy switch from mid-cap to real magazine capacity. One-piece magazine shell providing more durability. Made of fiber-reinforced polymer. Applied with high strength material providing high-quality external texture. The special design of the follower makes sure no BB left after the final shot. Compatible with most AEG at the market, including Arcturus, Ares, Cyma, APS, G&G, E&L, etc.