TSD Tactical WE Hi-Capa and Caspian Tradmarked 1911 GBB 5.1 Model 31 Round CO2 Airsoft Magazine Metal 31 round CO2 magazine Remove magazine base to access CO2 chamber Compatible with all TSD Tactical Caspian Trademark models, 3.8, 4.3, 5.1, 7.0 and custom SDWE01ARB Compatible with WE Hi-Capa 1911 gas blowback models This item is not for sale in some specific zip codes