Rezista Mainspring #123½ for Gruen caliber 311, 400, 405 - Steel

Rezista No. 123½ mainspring for Gruen caliber 311, 400, 405 movements, and quite likely many others, 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 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.