NuVigor Mainspring No. 64A for Bulova 10AB, 10AE, 10AN, 10AR, 10AA, 10AAL, 10AT, 10AW - Steel

NuVigor No. 65A steel mainspring for Gruen caliber 142, 143, 325, 385, Bulova caliber 4AF, 4AH, 4AN, 4AS, 4AW, 4AZ, 10AB, 10AE, 10AN, 10AR, 10AA, 10AAL, 10AT, 10AW movements, and perhaps others. 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.