Nivaflex Unbreakable Mainspring for MST caliber 378 - Alloy

Nivaflex Unbreakable mainspring N7150 for MST caliber 378 movements plus perhaps other similar ébauche movements as well, alloy, 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.