Swartchild Black Shield Mainspring for Waltham 6s Factory No. 2219 - Steel

Swartchild & Co Black Shield Mainspring No.4338 for Waltham 6s, Factory No. 2219, steel, new in envelope. Swartchild Mainspring Catalog (which I sell) lists this as a Dennison 12 x 7. 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 pretty good job of representing the item.