G.W.M.&S. Mainspring for Elgin 18s No. 812 - Steel

G.W.M.&S. Co. Mainspring for Elgin 18s, Factory No. 812, steel, new in envelope. Measures Dennison 20 x 1 so it's primarily for lower jewel movements.  I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a suitable job of representing the item.