Hamilton Factory Dynavar Mainspring for 22/0s Hamilton No. 717600- Alloy

Hamilton Factory Dynavar Mainspring for 22/0s Movements, Catalog No. 717600, alloy, new in envelope. Made for Grades 911 & 911M, and perhaps others. I likely have several of these so the one you get may not be identical in appearance but it will be the same factory Hamilton mainspring. 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.