HR Mainspring A733 for Waltham 0s Factory No. 2230 - Steel

HR Mainspring A733 for 0s Waltham Model 1907, Factory No. 2230, 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 an adequate job of representing the item.