Marco Mainspring #3028 for Gruen 405, 405SS, 406, 410, 411, 420, 421, 425, 426 - Steel

Marco steel mainspring #3028 for Gruen 405, 405SS, 406, 410, 411, 420, 421, 425, 426, 835, 835SS, 881, 881SS caliber movements plus perhaps several others, new in envelope. See images for all supported calibers and precise mainspring specifications. 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.