Nivaflex Unbreakable Mainspring N5107 for Universal 245, 257 - Alloy

Nivaflex Unbreakable Mainspring N 5107 for Universal 245, 257 caliber movements plus perhaps other similar ébauche watches, alloy, new in envelope. See images for 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.