Deckard is right , it is a Romanian PSL heavily modified to fit the SVT40. It required reshaping of the front catch , narrowing of the upper part of the body , reshaping the "lips" , completely removing the rear catch and TIG welding a new one about 1/2" higher. After all this it fits like a glove with no annoying rattling associated with the original SVT mag. Some mods to the follower were also required but these were minor and kinda obvious after the upper body was narrowed. IT FEEDS PROPERLY.