HR Mainspring SA309 for 16s Hampden No. 5697 - Alloy

HR Mainspring SA309 for Hampden 16s Movements, Factory No. 5697, alloy, new in envelope. See images for precise mainspring specifications. I likely have several of these s he one you get may differ slightly from the images. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.