HR Ev-R-Last Mainspring E312 for Buren 875, Chezard 40, Eterna 675 - Steel

HR Ev-R-Last Mainspring E312 for Buren 875, Chezard 40, Eterna 675 and likely other similar ébauche movements, steel, new in frail envelope. See image for precise 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 suitable job of representing the item.