S&T produces high-capacity magazines for their S&T Type 64 Airsoft AEG rifle, generally holding between 380 and 450 rounds of 6mm BBs. These are specifically designed for the proprietary S&T Type 64 platform and are not cross-compatible with other airsoft guns. 
 
Product Details
Capacity: The stated capacity varies slightly by retailer, with some listing 380 rounds, others 390 rounds, and some up to 450 rounds. All fall within the high-capacity (hi-cap) magazine category, which typically uses a winding mechanism to feed BBs.
Material: The magazines are constructed from a durable metal alloy, mirroring the authentic feel of the real steel Howa Type 64 battle rifle they are based on.
Compatibility: They are solely compatible with the S&T Type 64 Airsoft AEG rifles. The real Type 64 rifle uses a 20-round box magazine and was never exported outside of Japan's defense forces, making the airsoft replica and its magazines a unique item.