Hamilton 18s Mainspring Factory No. 14 for 23j Movements - Steel

Hamilton Mainspring for 18s 23j Motor Barrel Movements, Factory No. 14, steel, in replacement envelope. I have every reason to believe this is a factory Hamilton mainspring but the original envelope is missing so I'll cut you a deal on it. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.