HR Mainspring No. 939 for Valjoux caliber 60 Chronograph - Steel

HR steel mainspring No. 939 for Valjoux caliber 60 Chronograph movements and perhaps others, 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.