Nivaflex Unbreakable Mainspring N4182 for Aurore 121, 122, 126, Font 61, 120, 123, 180 +many more - Alloy

Nivaflex Unbreakable mainspring N 4182 for Angelus 56, Aurore 121, 122, 126, Benrus AB, AG, AI, Bulova 6AH, 6AU, 6AZ, 6BK, 6BL, 6BS, 6BU, Font 61, 120, 123, 180, Tavannes 420 to 426, Westfield 6WH, 6WM caliber movements plus perhaps other similar ébauche movements as well, alloy, new in envelope. See images for all supported calibers and 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.