Rezista Mainspring 1004 for Buren caliber 690, 691, Elgin Grade 677, 846, 847 - Steel

Rezista Mainspring No. 1004 for Buren caliber 690, 691, Elgin grade 677, 846, 847 movements, steel, new in envelope.   See images for precise mainspring specification.  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 an adequate job of representing the item.