Newall Security Mainspring #1313 for Gruen caliber 80, 540, 541, 542 - Steel

Newall Security Mainspring No. 1313 for Gruen caliber 80, 540, 541, 542 movements and perhaps others as well, steel, 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.