“NINE BALL Hi Capa HPA/M4 Magazine Adapter” will allow you to use HPA (High-Pressure Air)  M4 AEG magazines with any Hi-Capa Gas Blowback series pistols.

HPA ensures stable performance and eliminates inconsistencies which can often be affected by changing temperatures or gas pressures, making your airsoft pistol more reliable.

Additionally, using M4 magazines significantly boosts the ammunition capacity beyond what's possible with regular pistols, even when using “extended magazines”.
This adapter is ideal for the player that enjoys offensive play styles, who wants to engage swiftly and aggressively with their lightweight airsoft pistols.