WATCH-CRAFT Mainspring 3047W for MST 288, 299, Otero 37, 39, 137, 139, 391, 1371, 1391 - Alloy

WATCH-CRAFT Mainspring 3047W for MST 288, 299, Otero 37, 39, 137, 139, 391, 1371, 1391, Derby 126, 127, Kasper 500, 679 caliber movements plus perhaps similar ébauche watches, white alloy, 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.