Marco Mainspring #207 for 18s Waltham Keywind # 2206 - Steel

Marco (C&E Marshall) Mainspring No.207 for 18s Waltham Model 1870 Keywind Crescent St and perhaps others, Factory No. 2206, T-end, steel, new in very frail envelope. See image for further details. 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.