Samson Mainspring No. 10535 for Buren 690, 691, 35/12 - Steel

Samson Mainspring No. 10545 for Buren 690, 691, 35/12 caliber movements and perhaps others as well, steel, new in envelope. See images for precise mainspring specifications. 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.