Marco Mainspring No. 3000 for Gruen 300, 350, 530, 531 - Steel

Marco No. 3000 steel mainspring for Gruen caliber 300, 350, 530, 531 and perhaps others, new in envelope. See images for precise mainspring specifications. I likely have several of these so the one you get may differ slightly from the images. I specialize is 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.