GSG GSGGERMMP40925 OEM Blued Detachable 25rd 9mm Luger for GSG MP40
https://www.tandktactical.com/shop/813393019722-gsg-gsggermmp40925-oem-blued-detachable-25rd-9mm-luger-for-gsg-mp40-5028
https://www.tandktactical.com/web/image/product.template/5028/image_1920?unique=0afcac3
This replacement or spare magazine is compatible with your GSG MP40. *Note- it will not function in original WWII MP-40 firearms.
