Hamilton Dynavar 16s Mainspring No. 717040 for 992B & 950B - Alloy

Hamilton Dynavar Mainspring for 16s 21j 992B & 950B Movements, Factory No. 717040 / 35433, alloy, new in envelope. See image for precise characteristics. 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 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.