E&H Mainspring for Hamilton 12s Model 400 Movements No. 3328 - Steel

E&H Mainspring for Hamilton 12s Model 400 Movements, Factory No. 3328, steel, new in envelope. See image for specifications and further details. I 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 a pretty good job of representing the item.