The Promag FNH-A10 is a 21-round magazine designed to fit the FN Five-seven USG pistol chambered in 5.7x28mm. The magazine is constructed from steel and features a blued finish, giving it a black appearance. It's intended to provide FN Five-seven USG owners with an extended magazine capacity compared to the standard magazines that come with the pistol.
Promag is a company known for producing aftermarket magazines and accessories for various firearms, including handguns. The FNH-A10 magazine aims to enhance the capacity and functionality of the FN Five-seven USG pistol.