RN Mainspring for Waltham 7½ ligne Model 750B No. 2250 - Steel

RN Mainspring for Waltham 7½ ligne Model 750B Running Barrel movements, Factory No. 2250, steel, new in envelope. See images for precise mainspring specifications. 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.