Gruen Factory Mainspring for caliber 275, 280 movements - Alloy

Gruen Factory Mainspring for caliber 275, 280 movements, and quite likely others, alloy, new in open envelope. I likely have several of there so the one you get may differ slightly from the images. 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.