PM Mainspring for ETA caliber 651, Bulova caliber 4AT - ONYX Steel

PM ONYX steel mainspring for ETA caliber 651, Bulova caliber 4AT movements and quite likely others as well, 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.