Hamilton Factory Mainspring for 0s Hamilton No. 1536 - Steel

Hamilton Factory Mainspring for 0s Movements, No. 1536 (or 2118), steel, new in envelope. See image for precise characteristics. I likely have several of these so the one you get may differ slightly from the images. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do an adequate good job of representing the item.