Marco Mainspring #3801 for FEF 370-372, Kurth 270-275, 340-344, Tudor 374 - Steel

Marco Mainspring No. 3801 for Fleurier caliber 370-372, Kurth caliber 270-275, 340-344, Tudor caliber 374, ST caliber 30, 31, 60, 61, GP caliber 57, Elgin grade 748, steel, new in envelope. See images for precise mainspring specifications. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do an adequate job of representing the item.