Newall Security Mainspring #309 for Longines 10.39 caliber movement - Steel

Newall Security Mainspring No. 309 for Longines caliber 10.39 movements and perhaps other wrist watches as well, Longines T-end, 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.