HR Mainspring No. 726 for Norwich caliber 611 Timer - Steel

HR Mainspring No. 726 for Norwich caliber 611 Timer, steel, new in envelope. Norwich watches were made by numerous makers and I've yet to discover who manufactured the caliber 611, but I will post it if I find out. See image for precise mainspring specifications and further helpful information. I specialize in 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.