Kilb-Beck Mainspring #3900 for Hamilton 18s No. 14 - Steel

Kilb-Beck Company Mainspring #3900 for Hamilton 18s movements, Factory No. 14, steel, Hook or Wide Brace (W.B.) end, new in envelope. See image for precise mainspring specifications. Not very familiar with the supply house and would love to find them in a catalog somewhere. I likely have several of these so the on you get may differ slightly from the images. I specialize is hard to find watch parts so I usually have whatever you might need and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.