Trutex Unbreakable Mainspring for Gruen 405 to 430 - Alloy

Trutex Unbreakable Mainspring for Gruen caliber 405, 406, 410, 411, 420, 421, 425, 426, 430 plus perhaps other similar ébauche movements as well, alloy, new in open 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.