Sandsteel Mainspring for Hampden 16s No. #4697 - Steel

Sandsteel Mainspring for Hampden 16s RR movements, Factory No. 4697, steel, new in envelope. This mainspring comes with a half-T end or what someone else called a side-hook. See image for further details and specifications. I likely have several of these so the one you get may differ very 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.