HR Mainspring A601 for South Bend 16s No. 17528 - Steel

HR Mainspring A601 for South Bend 16s, No. 17528, T-end, steel, new in frail envelope. See image for further details and precise mainspring specifications. I may 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