CYY Mainspring for Howard 16s Mainspring No. 2323 (328) - Steel

CYY Mainspring for Howard Mainspring for 16s, Factory No. 2323, most (but not all) are marked with the maker CYY on the actual spring, see images for further details. Evidently the CYY P/N was 74 and while the Old Factory No is 2323, which is largely equivalent to a 328 which measures between 2.75 and 2.80mm, depending on your reference guide. It's worth noting that the Swartchild Guides do show the 328 as a Dennison 20 while others usually show it as Dennison 19 (see last image). I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do an adequate but perhaps somewhat incomplete job of representing the item.