Illinois Factory Mainspring #47370 for 6/0s hunting movements - Steel

Illinois Factory Mainspring No. 47370 for 6/0s hunting wrist watch movements, steel, new in frail envelope. One of the beautiful thing about factory mainsprings is that they pretty much always fit. See images for further details. I likely have several of these so the one you get may differ slightly from the images. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a marginally adequate job of representing the item.