They start out life as two German contract magazines and are meticulously welded together to create a monster 50 round 9mm magazine. Each mag is disassembled, welded together, inspected after welding, followers are checked for smooth movement, and new, longer, stiffer springs are added and the magazine is completely refinished in durable black oxide. (3-4 weeks on this custom item) Please call if you have any questions. Fits all 9mm UZI guns. Speed loader is recommended for loading.*Please allow 3-4 weeks for this custom magazine to be shipped.