Marco Mainspring #3340 for Tavannes caliber 504, 507, 584, 587 - Steel

Marco No. 3340 steel mainspring for Tavannes caliber 504, 507, 587, 587 movements plus likely 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.