Marco Mainspring #311 for 16s Hampden No. 3696 - Steel

Marco Mainspring #311 for 16s Hampden Bridge Model 1902 to 08 Pocket Watches (not the ¾ plate), Factory No. 3696, T-end, steel, new in envelope. See images for precise mainspring specifications.  I likely have several of these so the one you get may differ slightly from the images. I specialize is hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.