Swisscraft Mainspring #2708 for Gruen caliber 290, 291 - Steel

Swisscraft Mainspring #2708 for Gruen caliber 290, 291 movements, steel, 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 in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.